Biology

Question 1

Cell theory

Answer 1

1. All living things are made of cells
2. The cell is basic functional unit of life
3. All cells arise from other cells
4. Genetic information is carried in the form of deoxyribonucleic acid (DNA) and is passed from parent to daughter cell

Question 2

Nucleus

Answer 2

Stores genetic information and is the site of transcription

Question 3

Mitochondrion

Answer 3

Involved in ATP production and apoptosis

Question 4

Lysosome

Answer 4

Contain hydrolytic enzymes that break down molecules ingested through endocytosis and cellular waste products
Can also be involved in apoptosis when its enzymes are released

Question 5

Rough endoplasmic reticulum

Answer 5

Synthesizes proteins destined for secretion

Question 6

Smooth endoplasmic reticulum

Answer 6

Involved in lipid synthesis and detoxification

Question 7

Golgi apparatus

Answer 7

Packages, modifies and distributes cellular products

Question 8

Peroxisome

Answer 8

Break down very long chain fatty acids, synthesize lipids and contribute to the pentose phosphate pathway
Dependent on hydrogen peroxide for function
Participate in phospholipid synthesis

Question 9

Cytoskeletal elements

Answer 9

Microfilaments, microtubules, intermediate filaments, centrioles and flagella

Question 10

Which proteins make up microfilaments?

Answer 10

Actin

Question 11

Which proteins make up microtubules?

Answer 11

Tubulin

Question 12

Which proteins make up intermediate filaments?

Answer 12

Keratin, design, vimentin and lamins (depending on cell type)

Question 13

Centrioles

Answer 13

Consist of nine triplets of microtubules around a hollow center
Found in centrosomes
Involved in microtubule organization in the mitotic spindle

Question 14

Components of flagella

Answer 14

Consist of nine doublets of microtubules on the outside and two microtubules on the inside

Question 15

What do fibroblasts produce?

Answer 15

Collagen

Question 16

Are fibroblasts epithelial cells or connective tissue?

Answer 16

Connective tissue

Question 17

Endothelial cells

Answer 17

Line blood vessels

Question 18

Are endothelial cells epithelial cells or connective tissue?

Answer 18

Epithelial cells

Question 19

Alpha-cells

Answer 19

Produce glucagon in the pancreas

Question 20

Are alpha-cells epithelial cells or connective tissue?

Answer 20

Epithelial cells

Question 21

Osteoblasts

Answer 21

Produce osteoid

Question 22

Osteoid

Answer 22

The material that hardens into bone

Question 23

Are osteoblasts epithelial cells or connective tissue?

Answer 23

Connective tissue

Question 24

Chondroblasts

Answer 24

Produce cartilage

Question 25

Are condroblasts epithelial cells or connective tissue?

Answer 25

Connective tissue

Question 26

Where do archaea live?

Answer 26

Live in harsh environments

Use alternative sources of energy

Question 27

Shapes of bacteria

Answer 27

Cocci, bacilli and spirilli

Question 28

Cocci

Answer 28

Bacteria that is spherical

Question 29

Bacilli

Answer 29

Bacteria that is rod-shaped

Question 30

Spirilli

Answer 30

Bacteria that is spiral-shaped

Question 31

Obligate aerobe

Answer 31

Can survive when oxygen is present
Can carry out aerobic metabolism when oxygen is present
Cannot survive when oxygen is absent
Cannot carry out anaerobic metabolism when oxygen is absent

Question 32

Facultative anaerobe

Answer 32

Can survive when oxygen is present
Can carry out aerobic metabolism when oxygen is present
Can survive when oxygen is absent
Can carry out anaerobic metabolism when oxygen is absent

Question 33

Obligate anaerobe

Answer 33

Cannot survive when oxygen is present
Cannot carry out aerobic metabolism when oxygen is present
Can survive when oxygen is absent
Can carry out anaerobic metabolism when oxygen is absent

Question 34

Aerotolerant anaerobe

Answer 34

Can survive when oxygen is present
Cannot carry out aerobic metabolism when oxygen is present
Can survive when oxygen is absent
Can carry out anaerobic metabolism when oxygen is absent

Question 35

Can obligate aerobe survive with oxygen?

Answer 35

Yes

Question 36

Can obligate aerobe carry out aerobic metabolism when oxygen is present?

Answer 36

Yes

Question 37

Can obligate aerobe survive without oxygen?

Answer 37

No

Question 38

Can obligate aerobes carry out anaerobic metabolism when oxygen is absent?

Answer 38

No

Question 39

Can facultative anaerobe survive with oxygen?

Answer 39

Yes

Question 40

Can facultative anaerobe carry out aerobic metabolism when oxygen is present?

Answer 40

Yes

Question 41

Can facultative anaerobe survive without oxygen?

Answer 41

Yes

Question 42

Can facultative anaerobe carry out anaerobic metabolism when oxygen is absent?

Answer 42

Yes

Question 43

Can obligate anaerobe survive with oxygen?

Answer 43

No

Question 44

Can obligate anaerobe carry out aerobic metabolism when oxygen is present?

Answer 44

No

Question 45

Can obligate anaerobe survive without oxygen?

Answer 45

Yes

Question 46

Can obligate anaerobe carry out anaerobic metabolism when oxygen is absent?

Answer 46

Yes

Question 47

Can aerotolerant anaerobe survive with oxygen?

Answer 47

Yes

Question 48

Can aerotolerant anaerobe carry out aerobic metabolism when oxygen is present?

Answer 48

No

Question 49

Can aerotolerant anaerobe survive without oxygen?

Answer 49

Yes

Question 50

Can aerotolerant anaerobe carry out anaerobic metabolism when oxygen is absent?

Answer 50

Yes

Question 51

Gram-positive bacteria

Answer 51

Have a thick layer of peptidoglycan and lipoteichoic acid

Contain no outer membrane

Question 52

Gram-negative bacteria

Answer 52

Have a thin layer of peptidoglycan

Have an outer membrane containing lipopolysaccharides and phospholipids

Question 53

Eukaryotic flagella

Answer 53

Contain microtubules composed of tubulin, organized in a 9+2 arrangement

Question 54

Bacterial flagella

Answer 54

Made of flagellin and consist of a filament, a basal body and a hook

Question 55

Mechanisms of bacterial genetic recombination

Answer 55

Transformation, conjugation and transduction

Question 56

Transformation

Answer 56

The acquisition of genetic material from the environment that can be integrated into the bacterial genome

Question 57

Conjugation

Answer 57

The transfer of genetic information from one bacterium to another across a conjugation bridge

Question 58

Transduction

Answer 58

The transfer of genetic material from one bacterium to another using a bacteriophage as a vector

Question 59

What can be transferred across a conjugation bridge?

Answer 59

A plasmid can be transferred from F+ cells to F- cells

Or

A portion of the genome can be transferred from Hfr cell to a recipient

Question 60

Four phases of bacterial growth curve

Answer 60

Lag phase, exponential phase, stationary phase and death phase

Question 61

Lag phase

Answer 61

Bacteria gets used to environment; little growth during this time

Question 62

Exponential (log) phase

Answer 62

Bacteria use available resources to multiply at an exponential rate

Question 63

Stationary phase

Answer 63

Bacterial multiplication ceases as resources are used up

Question 64

Death phase

Answer 64

Bacteria die as resources become insufficient to support the colony

Question 65

Why are viruses considered obligate intracellular parasites?

Answer 65

Because they do not contain organelles such as ribosomes; therefore, in order to reproduce and synthesize proteins, they must infect cells and hijack their cellular machinery

Question 66

The pathway of retroviral nucleic acids from infection of a host cell to release of viral progeny

Answer 66

Nucleic acid enters as single-stranded RNA –> RNA undergoes reverse transcription (using reverse transcriptase) to form double-stranded DNA –> DNA can enter the host genome and replicate with the host cell –> DNA is transcribed to mRNA –> mRNA can be used to make structural proteins –> mRNA doubles as the viral genome for new virions –> virions are assembled from the structural proteins and mRNA genome –> virions can be released to infect other cells

Question 67

Lytic cycle

Answer 67

Bacteriophages replicate in the host cell in extremely high numbers until the host cell lyses and releases the virions

Question 68

Lysogenic cycle

Answer 68

Bacteriophage genome enters the host genome and replicates with the host cell as a provirus. At some point (after exposure to a particular stimulus), the provirus leaves the host genome and can be used to synthesize new virions

Question 69

How do prions cause disease

Answer 69

They cause disease by triggering a change in the conformation of a protein from an alpha-helix to a beta-pleated sheet. This change reduces solubility of the protein and makes it highly resistant to degradation

Question 70

Why are viruses not considered living things?

Answer 70

They are acellular, cannot reproduce without the assistance of a host cell, and many contain RNA as their genetic material

Question 71

Nucleolus

Answer 71

A subsection of the nucleus in which ribosomal RNA (rRNA) is synthesized

Question 72

Microfilaments

Answer 72

Composed of actin
Provide structural protection for the cell
Can cause muscle contraction through interactions with myosin
Help form the cleavage furrow during cytokinesis in mitosis

Question 73

Microtubules

Answer 73

Composed of tubulin
Create pathways for motor proteins like kinesis and dynein to carry vesicles
Contribute to the structure of cilia and flagella, where they are organized into nine pairs of microtubules in a ring with two microtubules at the center (9+2 structure)

Question 74

Intermediate filaments

Answer 74

Involved in cell-cell adhesion or maintenance of the integrity of the cytoskeleton
Help anchor organelles

Question 75

Epithelial tissues

Answer 75

Cover the body and line its cavities, protecting against pathogen invasion and desiccation
Form parenchyma
Polarized (one side facing the lumen and the other facing the outside)

Question 76

Parenchyma

Answer 76

The functional parts of the organ

Question 77

Classifications of epithelia

Answer 77

Simple epithelia, stratified epithelia and pseudostratified epithelia

Question 78

Simple epithelia

Answer 78

Have one layer

Question 79

Stratified epithelia

Answer 79

Have many layers

Question 80

Pseudostratified epithelia

Answer 80

Appear to have multiple layers because of differences in cell heights, but actually have one layer

Question 81

Epithelia shapes

Answer 81

Cuboidal cells, columnar cells, squamous cells

Question 82

Connective tissue function

Answer 82

Support and provide a framework for epithelial cells

Form the stroma by secreting materials to form an extracellular matrix

Question 83

Stroma

Answer 83

Support structure

Question 84

Examples of connective tissues

Answer 84

Bone, cartilage, tendons, ligaments, adipose tissue and blood

Question 85

How to classify bacteria?

Answer 85

Gram staining bacteria with crystal violet stain, followed by a counterstain with safranin. Gram-positive bacteria turn purple. Gram-negative bacteria turn pink-red.

Question 86

Chemotaxis

Answer 86

Moving in response to chemical stimuli

Question 87

How do prokaryotes carry out the electron transport chain?

Answer 87

Using the cell membrane

Question 88

Prokaryotic ribosomes

Answer 88

30S and 50 S

Question 89

Eukaryotic ribosomes

Answer 89

40S and 60S

Question 90

Binary fission

Answer 90

The prokaryote’s chromosome replicated while the cell grows in size, until the cell wall begins to grow inward along the midline of the cell and divides it into two identical daughter cells

Question 91

Plasmids

Answer 91

Carry extrachromosomal material

Contain antibiotic resistance genes

Question 92

Virulence factors

Answer 92

Antibiotic resistance genes

Question 93

Episomes

Answer 93

Plasmids that can integrate into the genome

Question 94

Transpons

Answer 94

Genetic elements that can insert into or remove themselves from the genome

Question 95

Capsid

Answer 95

A protein coat in a virus

Question 96

Bacteriophages

Answer 96

Viruses that target bacteria
Contain a tail sheath, which injects the genetic material into a bacterium
Contain a tail fiber, which allows the bacteriophage to attach to the host cell

Question 97

Positive sense viruses

Answer 97

Single-stranded RNA can be translated by the host cell

Question 98

Negative sense viruses

Answer 98

A complementary strand to the single-stranded RNA must be synthesized using RNA replicase, which can then be translated

Question 99

Retroviruses

Answer 99

Contain a single-stranded RNA genome, to which a complementary DNA is made using reverse transcriptase
The DNA strand can then be integrated into the genome

Question 100

Viroids

Answer 100

Plant pathogens that are small circles of complementary RNA that can turn off genes, resulting in metabolic and structural derangements of the cell and, potentially, cell death

Question 101

Can a virus have single-stranded DNA?

Answer 101

Yes

Question 102

Can a virus have double-stranded DNA?

Answer 102

Yes

Must use the cell’s RNA polymerase machinery in the nucleus to make its own mRNA

Question 103

Can a virus have single-stranded RNA?

Answer 103

Yes

Question 104

Can a virus have double-stranded RNA?

Answer 104

Yes

Question 105

How are archaea similar to bacteria?

Answer 105

They are single-celled organisms that lack a nucleus or membrane-bound organelles, contain a single circular chromosome, divide by binary fission or budding

Question 106

How are archaea similar to eukaryotic cells?

Answer 106

They start translation with methionine, contain similar RNA polymerases and associate their DNA with histones

Question 107

What kind of genetic information can viruses have?

Answer 107

Either single-stranded or double-stranded DNA or RNA

Question 108

Cell cycle stages

Answer 108

G0, G1, S, G2, M

Question 109

G0 stage

Answer 109

The cell performs its normal functions and it is not planning to divide

Question 110

G1 stage (presynthetic gap)

Answer 110

Cell grows and performs its normal functions. DNA is examined and repaired

Cells create organelles for energy and protein production, while also increasing their size
Has the restriction point

Question 111

S stage (synthesis)

Answer 111

Replication of DNA and sister chromatids are held together at the centromeres

Question 112

G2 stage (post synthetic gap)

Answer 112

Cell continues to grow and replicates organelles in preparation for mitosis. Cell continues to perform its normal function

Question 113

M stage

Answer 113

Mitosis

Question 114

Mitotic phases

Answer 114

Prophase, metaphase, anaphase, telophase and cytokinesis

Question 115

Prophase

Answer 115

Nuclear membrane disappears, chromosomes become tightly coiled, centrioles move to opposite poles of the cell and begin to form the spindle apparatus and spindle fibers attach at the kinetochore of each chromosome

Question 116

Metaphase

Answer 116

Centrioles align chromosomes along the midline of the cell (metaphase plate) using spindle fibers

Question 117

Anaphase

Answer 117

Spindle fibers pull sister chromatids apart so there’s a set of chromosomes on either pole of the cell

Question 118

Telophase and cytokinesis

Answer 118

Organelles separate moving to either pole of the cell, cell membrane splits the cell in half with each half having its own genetic material and organelles, nuclear membrane re-forms in each identical daughter cell, chromosomes loosen up and the spindle apparatus breaks down

Question 119

What is the ploidy of the daughter cells produced from meiosis I?

Answer 119

Two haploid daughter cells

Question 120

What is the ploidy of the daughter cells produced from meiosis II?

Answer 120

Four haploid daughter cells

Question 121

Homologous chromosomes

Answer 121

XX
Four copies of the same chromosome

Related chromosomes of opposite parental origin

Question 122

Sister chromatids

Answer 122

Identical copies of the came DNA that are held together at the centromere

| or X
Two copies of the same chromosome

Question 123

Meiosis I phases

Answer 123

Prophase I, metaphase I, anaphase I and telophase I

Question 124

Prophase I

Answer 124

Nuclear membrane disappears, chromosomes become tightly coiled, centrioles move to opposite poles of the cell and begin to form the spindle apparatus and spindle fibers attach at the kinetochore of each chromosome

Homologous chromosomes come together as tetrads during synapsis; crossing over

Question 125

Metaphase I

Answer 125

Centrioles align homologous chromosomes along opposite sides the midline of the cell (metaphase plate) using spindle fibers

Question 126

Anaphase I

Answer 126

Spindle fibers pull homologous chromosomes apart so there’s a set of chromosomes on either pole of the cell

Contromeres do not break

Question 127

Telophase I

Answer 127

Organelles separate moving to either pole of the cell, cell membrane splits the cell in half with each half having its own genetic material and organelles, nuclear membrane re-forms in each haploid daughter cell, chromosomes may or may not loosen up and the spindle apparatus dissolves

Question 128

Interstitial cells of Leydig

Answer 128

Secrete testosterone and other male sex hormones (androgens)

Question 129

Sertoli cells

Answer 129

Nourish sperm during their development

Question 130

During which phase of meiosis is a primary oocyte arrested?

Answer 130

Prophase I

Question 131

During which phase of meiosis is a secondary oocyte arrested?

Answer 131

Metaphase II

Question 132

Acrosome

Answer 132

Contains enzymes that are capable of penetrating the corona radiata and zone pellucid of the ovum, permitting fertilization to occur

Question 133

Which organelle forms the acrosome?

Answer 133

Golgi apparatus

Question 134

Phases of the menstrual cycle

Answer 134

Follicular phase, ovulation, luteal phase and menses

Question 135

Features of the follicular phase

Answer 135

Egg develops, endometrial lining becomes vascularized and glandularized

GnRH secretion stimulates FSH and LH secretion, which promotes follicle development –> Estrogen is released, stimulating vascularization and glandularization of the decidua

Question 136

Features of ovulation

Answer 136

Egg is released from follicle into peritoneal cavity

Stimulated by sudden surge in LH

Question 137

Features of the luteal phase

Answer 137

Corpus luteum produces progesterone to maintain the endometrium

LH promotes the ruptured follicle to become the corpus luteum, which secretes progesterone, which maintains the uterine lining –> High estrogen and progesterone levels cause negative feedback on GnRH, FSH and LH

Question 138

Features of menses

Answer 138

Shedding of endometrial lining

Estrogen and progesterone levels drop –> endometrial lining is sloughed off –> the block on GnRH production is removed

Question 139

FSH levels in the follicular phase

Answer 139

High

Question 140

FSH levels in ovulation

Answer 140

High

Question 141

FSH levels in the luteal phase

Answer 141

Low

Question 142

FSH levels in menses

Answer 142

Low

Question 143

LH levels in the follicular phase

Answer 143

No changes

Question 144

LH levels in ovulation

Answer 144

Super high (LH spike)

Question 145

LH levels in the luteal phase

Answer 145

No changes

Question 146

LH levels in menses

Answer 146

Low

Question 147

Estrogen levels in the follicular phase

Answer 147

Low, then high

Question 148

Estrogen levels in ovulation

Answer 148

High

Question 149

Estrogen levels in the luteal phase

Answer 149

High

Question 150

Estrogen levels in menses

Answer 150

Low

Question 151

Progesterone levels in the follicular phase

Answer 151

Low

Question 152

Progesterone levels in ovulation

Answer 152

Low

Question 153

Progesterone levels in the luteal phase

Answer 153

High

Question 154

Progesterone levels in menses

Answer 154

Low

Question 155

Androgens

Answer 155

Male sex hormones

Question 156

Diploid (2n) cells

Answer 156

Have two copies of each chromosome

Question 157

Haploid (n) cells

Answer 157

Have one copy of each chromosome

Question 158

Interphase

Answer 158

G1, S and G2 phases

DNA is uncoils in the form of chromatin

Question 159

Restriction point

Answer 159

Present in G1
DNA is checked for quality
Must be passed for the cell to move into the S stage

Question 160

p53

Answer 160

Plays a role in the two major checkpoints of the cell cycle G1 to S and G2 to M

Question 161

Cyclins

Answer 161

Bind to cyclin-dependent kinases (CDK), phosphorylating and activating transcription factors for the next stage of the cell cycle

Question 162

Cancer

Answer 162

Occurs when cell cycle control becomes deranged, allowing damaged cells to undergo mitosis without regard to quality or quantity of the new cells produced
Cancerous cells may begin to produce factors that allow them to escape their site and invade or metastasize elsewhere

Question 163

Tetrad

Answer 163

Four chromatids of homologous chromosomes

Question 164

Which stage of meiosis represents Mendel’s second law (the law of independent assortment)?

Answer 164

Prophase I

Question 165

Which stage of meiosis represents Mendel’s first law (the law of segregation)?

Answer 165

Anaphase I

Question 166

Is meiosis II more similar to meiosis I or mitosis?

Answer 166

Mitosis, except the daughter cells are haploid

Question 167

X chromosome

Answer 167

Carries a sizable amount of genetic information

Question 168

Mutations of X-linked genes

Answer 168

Cause sex-linked disorders

Question 169

Hemizygous

Answer 169

Males because they have unpaired X chromosomes

Question 170

Who most often expresses sex-linked disorders?

Answer 170

Males because they are hemizygous for the X chromosome

Question 171

Who is most often a carrier to sex-linked disorders?

Answer 171

Women because they have two copies of the X chromosome

Question 172

Y chromosome

Answer 172

Carries little genetic information

Contains the SRY (sex-determining region Y) gene

Question 173

SRY (sex-determining region Y) gene

Answer 173

Present on Y chromosome

Causes gonads to differentiate into testes

Question 174

Where does sperm develop?

Answer 174

Seminiferous tubules in the testes

Question 175

How are sperm nourished?

Answer 175

By sertoli cells

Question 176

What secrets testosterone and androgens in the testes?

Answer 176

Interstitial cells of Leydig

Question 177

Epididymis

Answer 177

Stores sperm and gives it mobility

Question 178

Ejaculation pathway

Answer 178

Vas deferens –> ejaculatory duct –> urethra –> penis

Question 179

Seminal vesicles

Answer 179

Contribute fructose to nourish sperm and produce alkaline fluid

Question 180

Prostate gland

Answer 180

Produces alkaline fluid

Question 181

Bulbourethral glands

Answer 181

Produce clear viscous fluid that cleans out any remnants of urine and lubricates the urethra during sexual arousal

Question 182

Semen

Answer 182

Sperm + seminal fluid

Question 183

Spermatogenesis

Answer 183

Four haploid sperm are produced from a spermatogonium

Question 184

Primary spermatocytes

Answer 184

Germ cells after S phase

Question 185

Secondary spermatocytes

Answer 185

Germ cells after meiosis I

Question 186

Spermatids

Answer 186

Germ cells after meiosis II

Question 187

Spermatozoa

Answer 187

Germ cells after maturation

Question 188

Sperm parts

Answer 188

Head, midpiece and flagellum

Question 189

Sperm head

Answer 189

Contains genetic material and is covered with an acrosome

Question 190

Sperm midpiece

Answer 190

Generates ATP from fructose and contains many mitochondria

Question 191

Sperm flagellum

Answer 191

Promotes sperm mobility

Question 192

Where are ova (eggs) produced?

Answer 192

Follicles in the ovaries

Question 193

Where does an egg get ovulated each month?

Answer 193

Peritoneal sac and then it gets drawn into the Fallopian tube (oviduct)

Question 194

Where is sperm deposited during intercourse?

Answer 194

Vaginal canal

Question 195

Vulva

Answer 195

External female anatomy

Question 196

Oogenesis

Answer 196

One haploid ovum and a variable number of polar bodies are formed from an oogonium

Question 197

Primary oocyte

Answer 197

Present at birth and arrested in prophase I

Question 198

Secondary oocyte

Answer 198

Only one is present after every ovulation and arrested in metaphase II until either menses or fertilization

Question 199

When does an oocyte complete meiosis II?

Answer 199

When it is fertilized

Question 200

Zona pellucida

Answer 200

Surround the oocyte

Acellular mixture of glycoproteins that protect the oocyte and contain the compounds necessary for sperm binding

Question 201

Corona radiata

Answer 201

Surround the oocyte

A layer of cells that adhered to the oocyte during ovulation

Question 202

What releases gonadotropin-releasing hormone (GnRH)?

Answer 202

Hypothalamus

Question 203

Gonadotropin-releasing hormone (GnRH)

Answer 203

Causes the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH)

Question 204

Follicle-stimulating hormone (FSH) in males

Answer 204

Stimulates Sertoli cells

Trigger spermatogenesis

Question 205

Luteinizing hormone (LH) in males

Answer 205

Cause the interstitial cells to produce testosterone

Question 206

Testosterone

Answer 206

Responsible for the maintenance and development of the male reproductive system and male secondary sex characteristics (facial and axillary hair, deepening of the voice and changes in growth patterns)

Question 207

Follicle-stimulating hormone (FSH) in females

Answer 207

Stimulates ovarian follicles

Stimulate the production of estrogen and progesterone

Question 208

Luteinizing hormone (LH) in females

Answer 208

Causes ovulation

Stimulate the production of estrogen and progesterone

Question 209

Why does the sudden surge in LH occur?

Answer 209

Estrogen stops having negative feedback effects at a certain threshold and begins to have positive feedback effects

Question 210

What causes negative feedback on GnRH, LH and FSH levels?

Answer 210

High levels of estrogen and progesterone

Question 211

What happens if fertilization occurs?

Answer 211

The blastula produces human chorionic gonadotropin (hCG) which, as an LH analog, can maintain the corpus luteum

Question 212

What happens near the end of the first trimester?

Answer 212

hCG levels drop as the placenta takes over progesterone production

Question 213

Menopause

Answer 213

Occurs when the ovaries stop producing estrogen and progesterone (ages 45 and 55)
Menstruation stops
FSH and LH levels rise

Question 214

Sperm development

Answer 214

Spermatogonium –> primary spermatocyte –> secondary spermatocyte –> spermatid –> spermatozoan

Question 215

Vas deferens

Answer 215

Tube connecting the epididymis to the ejaculatory duct

Question 216

Cowper’s glands

Answer 216

Produce a fluid to clear traces of urine in the urethra

Question 217

What is the last point in the meiotic cycle in which the cell has a diploid number of chromosomes?

Answer 217

Telophase I

Question 218

Determinate cleavage

Answer 218

Cell division that results in cells having definitive lineages; that is, at least one daughter cell is already programmed to differentiate into a particular cell type

Question 219

Indeterminate cleavage

Answer 219

Cell division that results in cells that can differentiate into any cell type (or a whole organism)

Question 220

Stages of development from zygote to gastrula

Answer 220

Zygote –> 2-cell embryo –> 4-cell embryo –> 8-cell embryo –> 16-cell embryo –> morula –> blastula (blastocyst) –> gastrula

Question 221

During which stage of development does implantation occur?

Answer 221

Blastula (blastocyst)

Question 222

Primary Germ Layers

Answer 222

Ectoderm, mesoderm, endoderm

Question 223

Ectoderm

Answer 223

Nervous system, integumentary system, eyes and ears

Question 224

Mesoderm

Answer 224

Musculoskeletal system, circulatory system, excretory system, endocrine system, reproductive system, digestive system, respiratory system

Question 225

Endoderm

Answer 225

Epithelial linings of organs, liver, pancreas, thyroid, bladder, distal tracts of the excretory and reproductive systems

Question 226

Induction

Answer 226

The process by which nearby cells influence the differentiation of adjacent cells

Question 227

What tissues do neural crest cells develop into?

Answer 227

PNS and skin

Question 228

Why is induction important?

Answer 228

It insures the proper spatial location and orientation of cells that share function or have complementary functions

Question 229

Determination

Answer 229

The commitment of a cell to a particular lineage

Question 230

Differentiation

Answer 230

The actual changes that occur in order for the cell to assume the structure and function of the determined cell type

Question 231

Types of potency

Answer 231

Totipotency, pluripotency and multipotency

Question 232

Types of cell-cell communication

Answer 232

Autocrine, paracrine, juxtacrine and endocrine

Question 233

Apoptosis

Answer 233

Programmed cell death

Question 234

Necrosis

Answer 234

Cell death due to injury

Question 235

Totipotent cell lineages

Answer 235

Any cell type in the developing embryo (primary germ layers) or in extra-embryonic tissues (amnion, chorion, placenta)

Question 236

Pluripotent cell lineages

Answer 236

Any cell type in the developing embryo (primary germ layers)

Question 237

Multipotent cell lineages

Answer 237

Any cell type within a particular lineage (hematopoietic stem cells)

Question 238

Autocrine

Answer 238

The signal acts on the same cell that secreted it

Question 239

Paracrine

Answer 239

The signal acts on local cells

Question 240

Juxtacrine

Answer 240

The signal acts on an adjacent cell through direct receptor stimulation

Question 241

Endocrine

Answer 241

The signal travels via the bloodstream to act at distant sites

Question 242

What does apoptosis result in?

Answer 242

Contained blebs of the dead cell that can be picked up and digested by other cells

Question 243

What does necrosis result in?

Answer 243

Spilling of cytoplasmic contents

Question 244

What is the oxygenation status of the blood in the umbilical arteries?

Answer 244

Deoxygenated

Question 245

What is the oxygenation status of blood in the umbilical vein

Answer 245

Oxygenated

Question 246

Three fetal shunts

Answer 246

Foramen ovale, ductus arteriosus, ductus venosus

Question 247

What vessels or heart chambers does the foramen ovale connect?

Answer 247

Right atrium to left atrium

Question 248

What vessels or heart chambers does the ductus arteriosus connect?

Answer 248

Pulmonary artery to aorta

Question 249

What vessels or heart chambers does the ductus venosus connect?

Answer 249

Umbilical vein to inferior vena cava

Question 250

Which organ does the foramen ovale bypass?

Answer 250

Lungs

Question 251

Which organ does the ductus arteriosus bypass?

Answer 251

Lungs

Question 252

Which organ does the ductus venosus bypass?

Answer 252

Liver

Question 253

Key developmental features of the first trimester

Answer 253

Organogenesis

Question 254

Key developmental features of the second trimester

Answer 254

Growth, movement, face develops, digits elongate

Question 255

Key developmental features of the third trimester

Answer 255

Growth, brain development, transfer of antibodies to the fetus

Question 256

Organogenesis in the first trimester

Answer 256

Heart, eyes, gonads, limbs, liver and brain

Question 257

First phase of birth

Answer 257

Cervix thins and the amniotic sac ruptures

Question 258

Second phase of birth

Answer 258

Urine contractions and birth of the fetus

Question 259

What coordinates uterine contractions?

Answer 259

Prostaglandins and oxytocin

Question 260

Third stage of birth

Answer 260

Placenta and umbilical cord expulsion

Question 261

Fertilization

Answer 261

The joining of a sperm and an ovum

Question 262

Where does fertilization occur?

Answer 262

In the ampulla of the fallopian tube

Question 263

How does the sperm fertilize the egg (i.e. the cortical reaction)?

Answer 263

It uses ayrosomal enzymes to penetrate to corona radiata and zona pellucida –> Once it contacts the oocyte’s plasma membrane, the sperm establishes the acrosomal apparatus and injects its pronucleus –> When the first sperm penetrates, it causes the release of calcium ions, which prevents additional sperm from fertilizing the egg and increases the metabolic rate of the resulting diploid zygote

Question 264

Fraternal (dizygotic) twins

Answer 264

Result from the fertilization of two eggs by two different sperm

Question 265

Identical (monozygotic) twins

Answer 265

Result from the splitting of a zygote in two

Question 266

Cleavage

Answer 266

The early divisions of cells in the embryo

These mitotic divisions result in a larger number of smaller cells, as the overall volume does not change

Question 267

Why does a zygote become an embryo after the first cleavage?

Answer 267

Because it is no longer unicellular

Question 268

Morula

Answer 268

A solid mass of cells seen in early development

Question 269

Blastula (blastocyst)

Answer 269

Has a fluid-filled center called a blastocoel and has two different cell types, including trophoblasts and the inner cell mass

Question 270

Blastocoel

Answer 270

Fluid inside the center of a blastula

Question 271

Types of cells in a blastula

Answer 271

Trophoblasts and inner cell mass

Question 272

Trophoblasts

Answer 272

Become placental structures

Question 273

Inner cell mass

Answer 273

Become the developing organism

Question 274

Where does a blastula implant?

Answer 274

In the endometrial lining

Question 275

What happens after the blastula implants?

Answer 275

It forms the placenta

Question 276

Chorion

Answer 276

Penetrate the endometrium and create the interface between maternal and fetal blood using chorionic villi

Question 277

How is the embryo supported before the placenta forms?

Answer 277

Yolk sac

Question 278

Allantois

Answer 278

Involved in early fluid exchange between the embryo and the yolk sac

Question 279

Amnion

Answer 279

Lies inside the the chorion and produces amniotic fluid

Question 280

How is the developing organism connected to the placenta?

Answer 280

Via the umbilical cord

Question 281

Gastrulation

Answer 281

The archenteron is formed with a blastopore at the end. As the archenteron grows through the blastocoel, it contacts the opposite side, establishing three primary germ layers (ectoderm, endoderm and mesoderm)

Question 282

Neurulation

Answer 282

The development of the nervous system

Question 283

When does neurulation occur?

Answer 283

After the formation of the three germ layers

Question 284

How does neurulation occur?

Answer 284

The notochord induces a group of overlying ectodermal cells to form neural folds surrounding a neural groove –> the neural folds fuse to form the neural tube, which becomes the CNS –> the tip of each neural fold contains neural crest cells

Question 285

What does the neural tube become?

Answer 285

CNS

Question 286

Teratogens

Answer 286

Substances that interfere with development, causing defects or even death of the developing embryo

Question 287

How does diabetes in pregnant women affect the fetus?

Answer 287

Increase fetal size and cause hypoglycemia after birth

Question 288

How does folic acid deficiency in pregnant women affect the fetus?

Answer 288

Neural tube defects

Question 289

How is determination accomplished?

Answer 289

Uneven segregation of cellular material during mitosis

Using morphogens

Question 290

Morphogens

Answer 290

Promote development down a specific cell line

Question 291

How can a cell respond to a morphogen?

Answer 291

It must have competency

Question 292

How is differentiation accomplished?

Answer 292

Via selective transcription to take on characteristics appropriate to its cell line

Question 293

Stem cells

Answer 293

Cells that are capable of developing into various cell types

Question 294

Totipotent cells

Answer 294

Able to differentiate into all cell types, including the three germ layers and placental structures

Question 295

Pluripotent cells

Answer 295

Able to differentiate into all three germ layers and their derivatives

Question 296

Multipotent cells

Answer 296

Able to differentiate only to a specific subset of cell types

Question 297

Inducer

Answer 297

Releases factors to promote the differentiation of a competent responder

Question 298

Growth factors

Answer 298

Peptides that promote differentiation and mitosis in certain tissues

Question 299

Reciprocal induction

Answer 299

When two tissues both induce further differentiation in each other

Question 300

How does signaling occur?

Answer 300

Via gradients

Question 301

Do cells migrate to arrive at their anatomically correct location?

Answer 301

Yes

Question 302

When is apoptosis useful?

Answer 302

Sculpting anatomical structures (e.g. removing webbing between digits)

Question 303

Regenerative capacity

Answer 303

The ability of an organism to regrow certain parts of the body

Question 304

Does the liver have high or low regenerative capacity?

Answer 304

High

Question 305

Does the heart have high or low regenerative capacity?

Answer 305

Low

Question 306

Does the kidneys have high or low regenerative capacity?

Answer 306

High

Question 307

Senescence

Answer 307

The result of multiple molecular and metabolic processes; most notably, the shortening of telomeres during cell division

Question 308

Where does nutrient, gas and waste exchange occur in the fetus?

Answer 308

At the placenta

Question 309

How are oxygen and carbon dioxide exchanged between the mother and fetus?

Answer 309

Passively through changes in concentration gradient

Question 310

Fetal hemoglobin (HbF)

Answer 310

Has a higher affinity for oxygen than adult hemoglobin (primarily HbA), which also assists in the transfer (and retention) of oxygen into the fetal circulatory system

Question 311

Placental barrier

Answer 311

Serves as the immune protect against many pathogens
Transfers antibodies from mother to fetus
Secretes estrogen, progesterone and human chorionic gonadotropin (hCG)

Question 312

Notochord

Answer 312

Forms from the mesoderm and causes neurulation

Question 313

Can a fetus produce immunoglobulins?

Answer 313

No, because they are immunologically naive

Question 314

Can fetal hemoglobin cross the placenta?

Answer 314

No, because it’s too large

Question 315

Is fetal hemoglobin the same size as adult hemoglobin?

Answer 315

No, it’s larger

Question 316

When do somatic cells stop dividing?

Answer 316

When the telomeres become too short to effectively protect genomic material

Question 317

Telomerase

Answer 317

An enzyme that allows for synthesis of telomeres to counteract telomere shortening during mitosis

Question 318

Why are embryonic stem cells controversial?

Answer 318

Because they require destruction of an embryo to harvest

Question 319

How can one increase the level of potency of adult stem cells?

Answer 319

Treatment with various transcription factors

Question 320

Would using one’s own stem cells remove the risk or rejection when the cells are introduced into an individual?

Answer 320

Yes

Question 321

Can adult stem cells be pluripotent?

Answer 321

Rarely so, unless pluripotency has been induced by strategic use of transcription factors

Question 322

Incomplete regeneration

Answer 322

Newly formed tissues are not identical in structure or function to the tissues that have been injured or lost (e.g. scars)

Question 323

What is the last structure to become fully functional in a fetus?

Answer 323

The lungs

Question 324

Axon

Answer 324

Transmits electrical signals (action potentials) from the soma to the synaptic knob

Question 325

Axon hillock

Answer 325

Integrates excitatory and inhibitory signals from the dendrites and fires an action potential if the excitatory signals are strong enough to reach threshold

Question 326

Dendrite

Answer 326

Receive incoming information signals and carry them to the soma

Question 327

Myelin sheath

Answer 327

Acts as insulation around the axon and speeds conduction
Prevents signal loss
Prevents the dissipation of the neural impulse and crossing of neural impulses from adjacent neurons

Question 328

Soma

Answer 328

The cell body of a neuron, contains the nucleus, ER and ribosomes

Question 329

Synaptic bouton (nerve terminal)

Answer 329

Lies at the end of the axon and releases neurotransmitters

Question 330

The collection of cell bodies in the CNS

Answer 330

Nucleus

Question 331

The collection of cell bodies in the PNS

Answer 331

Ganglion

Question 332

Astrocyte

Answer 332

Nourish neurons and form the blood-brain barrier

Question 333

Ependymal cell

Answer 333

Produce cerebrospinal fluid

Question 334

Microglia

Answer 334

Phagocytic cells that ingest and breakdown waste products and pathogens in CNS

Question 335

Oligodendrocyte

Answer 335

Produce myelin and the CNS

Question 336

Schwann cell

Answer 336

Produce myelin the PNS

Question 337

When does an axon hillock fire an action potential?

Answer 337

When the excitatory signals are strong enough to reach threshold

Question 338

Which part of the neuron fires an action potential?

Answer 338

The axon hillock

Question 339

Which part of the neuron releases neurotransmitters?

Answer 339

The synaptic bouton

Question 340

What produces myelin in the CNS?

Answer 340

Oligodendrocytes

Question 341

What produces myelin in the PNS?

Answer 341

Schwann cells

Question 342

How is the resting membrane potential maintained?

Answer 342

Sodium/potassium ATPase and selective permeability of ions

Question 343

What is the approximate voltage of the resting membrane potential?

Answer 343

-70 mV

Question 344

Temporal summation

Answer 344

The integration of multiple signals close to each other in time

Question 345

Spatial summation

Answer 345

The integration of multiple signals close to each other in space

Question 346

During the action potential, which ion channel opens first?

Answer 346

Sodium ion channels

Question 347

How are sodium ion channels regulated?

Answer 347

Inactivation, the opening of potassium ion channels, at +35 mV

Question 348

What effect does the opening of the sodium ion channel have on the polarization of the cell?

Answer 348

It depolarizes the cell

Question 349

During the action potential, which ion channel opens second?

Answer 349

Potassium ion channels

Question 350

How are potassium ion channels regulated?

Answer 350

Closing at low potentials (slightly below -70 mV)

Question 351

What effect does the opening of the potassium ion channel have on the polarization of the cell?

Answer 351

Repolarization of the cell and eventually hyper-polarization

Question 352

Absolute refractory period

Answer 352

It does not matter how much or how strong the stimuli are, no further action potential will be initiated

Question 353

Relative refractory period

Answer 353

Occurs during the hyper polarization phase

If strong enough stimulus is present, another action potential will be fired

Question 354

What ion is primarily responsible for the fusion of neurotransmitter-containing vesicles with nerve terminal membrane?

Answer 354

Calcium

Question 355

What are the three main methods by which a neurotransmitter’s action can be stopped?

Answer 355

Enzymatic degradation, reuptake and diffusion

Question 356

When do sodium ion channels open?

Answer 356

At -50 mV

Question 357

How can the inactivation of sodium ion channels be reversed?

Answer 357

By repolarizing the cell

Question 358

When do potassium ion channels open?

Answer 358

At +35 mV

Question 359

Central Nervous System (CNS)

Answer 359

Brain and spinal cord

Question 360

Peripheral Nervous System (PNS)

Answer 360

Afferent and efferent neurons

Question 361

Afferent neurons

Answer 361

Carry sensory information from the periphery to the CNS

Question 362

Efferent neurons

Answer 362

Carry information from the CNS to the periphery to initiate an action

Question 363

Somatic nervous system

Answer 363

Voluntary

Question 364

Autonomic nervous system

Answer 364

Involuntary

Question 365

Sympathetic nervous system

Answer 365

Fight or flight response
Increased heart rate, bronchial dilation, redistribution of blood to locomotor muscles, dilation of pupils, slowing of digestive and urinary function

Question 366

Parasympathetic nervous system

Answer 366

Rest and digest response
Slowed heart rate, bronchial constriction, redistribution of blood to the gut, promotion of exocrine secretions, constriction of pupils, promotion of peristalsis and urinary function

Question 367

Monosynaptic reflex

Answer 367

A sensory (afferent, presynaptic) neuron fires directly onto a motor (efferent, postsynaptic) neuron

Question 368

Polysynaptic reflex

Answer 368

A sensory (afferent, presynaptic) neuron may fire directly onto a motor neuron (efferent, postsynaptic) neuron, but interneurons are used as well. The interneurons fire onto other motor neurons.

Question 369

Neurons

Answer 369

Highly specialized cells responsible for the conduction of impulses

Question 370

Do neurons communicate through electrical or chemical forms?

Answer 370

Both

Question 371

How does electrical communication among neurons work?

Answer 371

Via ion exchange and the generation of membrane potentials down the length of the axon

Question 372

How does chemical communication among neurons work?

Answer 372

Via neurotransmitter release from the presynaptic cell and the binding of these neurotransmitters to the postsynaptic cell

Question 373

Nodes of Ranvier

Answer 373

Exposed areas of myelinated axons that permit saltatory conduction

Question 374

Synapse

Answer 374

Consist to the nerve terminal of the presynaptic neuron, the membrane of the postsynaptic cell, and the space between the two

Question 375

Synaptic cleft

Answer 375

The space between two neurons

Question 376

What are individual axons bundled into?

Answer 376

Nerves or tracts

Question 377

Can a single nerve carry multiple types of information?

Answer 377

Yes, including sensory, motor or both

Question 378

Can a single tract carry multiple types of information?

Answer 378

No

Question 379

Ganglia

Answer 379

Cell bodies of neurons of the same type within a nerve cluster in the PNS

Question 380

Nuclei

Answer 380

Cell bodies of the individual neurons within a tract cluster in the CNS

Question 381

Neuroglia (Glial cells)

Answer 381

Other cells within the nervous system in addition to neurons

Question 382

Blood-brain barrier

Answer 382

Controls the transmission of solutes from the bloodstream into nervous tissue

Question 383

Where are ependymal cells?

Answer 383

They line the ventricles of the brain

Question 384

Cerebrospinal fluid

Answer 384

Physically supports the brain and serves as a shock absorber

Question 385

Sodium/Potassium ATPase

Answer 385

Pumps three sodium ions out of the cell for every two potassium ions pumped in

Question 386

Excitatory signals

Answer 386

Cause a neuron to depolarize

Question 387

Inhibitory signals

Answer 387

Cause a neuron to hyperpolarize

Question 388

How are signals propagated down the axon?

Answer 388

Through an action potential

Question 389

Why does an impulse propagate down the length of the axon?

Answer 389

Because the influx of sodium in one segment of the axon brings the subsequent segment of the axon to threshold. The fact that the preceding segment of the axon is in its refractory period means that the action potential can only travel in one direction

Question 390

Where are neurotransmitters released from a neuron?

Answer 390

At the nerve terminal into the synapse

Question 391

What happens when the action potential arrives at the nerve terminal?

Answer 391

Voltage-gated calcium channels open

Question 392

Do calcium ions flow into or out of the neuron when the voltage-gated calcium channels open?

Answer 392

Into the neuron

Question 393

What happens when the voltage-gated calcium channels open?

Answer 393

Vesicles filled with neurotransmitter fuse with the presynaptic membrane, resulting in the exocytosis of neurotransmitter into the synaptic cleft, which then bind to their receptors on the postsynaptic cell

Question 394

How to stop the propagation of a signal?

Answer 394

Neurotransmitters must be cleared from the postsynaptic cleft through: enzymatic breakdown of the neurotransmitters, reabsorption of the neurotransmitter by the presynaptic cell through reuptake channels, the neurotransmitter can diffuse out the of the synaptic cleft

Question 395

What is the white matter in the CNS made of?

Answer 395

Myelinated axons

Question 396

What is the grey matter in the CNS made of?

Answer 396

Unmyelinated cell bodies and dendrites

Question 397

In the brain, is the white matter deeper than the grey matter?

Answer 397

Yes

Question 398

In the spinal cord, is the white matter deeper than the grey matter?

Answer 398

No

Question 399

Reflex arcs

Answer 399

Use the ability of interneurons in the spinal cord to relay information to the source of a stimulus while simultaneously routing it to the brain

Question 400

Action potential

Answer 400

All or nothing response

Question 401

Where do sensory neurons enter the spinal cord?

Answer 401

On the dorsal side

Question 402

Where do motor neurons exit the spinal cord?

Answer 402

On the ventral side

Question 403

Neurotransmitter released by pre-ganglionic neurons

Answer 403

Acetylcholine

Question 404

Is acetylcholine released by the parasympathetic or the sympathetic pre-ganglionic neurons?

Answer 404

Both

Question 405

What does a sympathetic post-ganglionic neuron release?

Answer 405

Epinephrine or norepinephrine

Question 406

What does a parasympathetic post-ganglionic neuron release?

Answer 406

Acetylcholine

Question 407

What color does gram-positive bacteria turn into after staining?

Answer 407

Purple

Question 408

What color does gram-negative bacteria turn into after staining?

Answer 408

Pink-red

Question 409

What does the tail sheath on a bacteriophage do?

Answer 409

Injects the genetic material into a bacterium

Question 410

What does the tail fiber on a bacteriophage do?

Answer 410

Allows the bacteriophage to attach to the host cell

Question 411

What is the chemical precursor for a peptide hormone?

Answer 411

Amino acids (polypeptides)

Question 412

What is the chemical precursor for a steroid hormone?

Answer 412

Cholesterol

Question 413

Where is the receptor fir a peptide hormone?

Answer 413

On the cell membrane

Question 414

Where is the receptor fir a steroid hormone?

Answer 414

Inside the cell

Question 415

What is the mechanism of action for a peptide hormone?

Answer 415

Stimulates a receptor (usually a G protein-coupled receptor), affecting levels of second messengers (commonly cAMP)
Initiates a signal cascade

Question 416

What is the mechanism of action for a steroid hormone?

Answer 416

Binds to a receptor, induces conformational change and regulates transcription at the level of the DNA

Question 417

What is the method of travel in the bloodstream for a peptide hormone?

Answer 417

Dissolves and travels freely

Question 418

What is the method of travel in the bloodstream for a steroid hormone?

Answer 418

Binds to a carrier protein

Question 419

How fast do the effects of a peptide hormone onset?

Answer 419

Very quickly

Question 420

How fast do the effects of a steroid hormone onset?

Answer 420

Very slowly

Question 421

What is the duration of action for a peptide hormone?

Answer 421

Short-lived

Question 422

What is the duration of action for a steroid hormone?

Answer 422

Long-lived

Question 423

How are amino acid-derivative hormones synthesized?

Answer 423

Amino acid-derivative hormones are made by modifying amino acids, such as the addition of iodine to tyrosine (in thyroid hormone production)

Question 424

Direct hormone

Answer 424

Secreted into the bloodstream and travel to a target tissue where they have direct effects

Question 425

Tropic hormone

Answer 425

Cause secretion of another hormone that then travels to the target tissue to cause an effect

Question 426

Hypothalamus hormones

Answer 426

Gonadotropin-releasing hormone (GnRH), corticotropin-releasing factor (CRF), thyroid-releasing hormone (TRH), dopamine and growth hormone-releasing hormone (GHRH)

Question 427

Gonadotropin-releasing hormone (GnRH)

Answer 427

Releases follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary

Question 428

Corticotropin-releasing factor (CRF)

Answer 428

Releases adrenocorticotropic hormone (ACTH) from the anterior pituitary

Question 429

Thyroid-releasing hormone (TRH)

Answer 429

Releases thyroid stimulating hormone (TSH) from the anterior pituitary

Question 430

Dopamine (Prolactin-inhibiting factor, PIF)

Answer 430

A decrease in dopamine promotes prolactin secretion by the anterior pituitary

Question 431

Growth hormone-releasing hormone (GHRH)

Answer 431

Releases growth hormone (GH) from the anterior pituitary

Question 432

What is the target organ of gonadotropin-releasing hormone (GnRH)?

Answer 432

Ovaries or testes

Question 433

What is the target organ of corticotropin-releasing factor (CRF)?

Answer 433

Adrenal cortex

Question 434

What is the target organ of thyroid-releasing hormone (TRH)?

Answer 434

Thyroid gland

Question 435

What is the target organ of dopamine?

Answer 435

Breast tissue

Question 436

What is the target organ of growth hormone-releasing hormone (GHRH)?

Answer 436

Muscles and bones

Question 437

What are the hormones released by the target organ of gonadotropin-releasing hormone (GnRH)?

Answer 437

Estrogen and progesterone or testosterone

Question 438

What are the hormones released by the target organ of corticotropin-releasing factor (CRF)?

Answer 438

Glucocorticoids (cortisol and cortisone)

Question 439

What are the hormones released by the target organ of thyroid-releasing hormone (TRH)?

Answer 439

Triiodothyronine (T3) and thyroxine (T4)

Question 440

Which two hormones are primarily involved in calcium homeostasis?

Answer 440

Calcitonin and parathyroid hormone

Question 441

Which endocrine tissue synthesizes catecholamines?

Answer 441

The adrenal medulla

Question 442

What are the two main catecholamines it produces?

Answer 442

Epinephrine and norepinephrine

Question 443

Which two pancreatic hormones are the major drivers of glucose homeostasis?

Answer 443

Insulin and glucagon

Question 444

Where does insulin come from?

Answer 444

Beta cells in the pancreas

Question 445

Where does glucagon come from?

Answer 445

Alpha cells in the pancreas

Question 446

What effect does insulin have on blood glucose?

Answer 446

Lowers it by stimulating glucose uptake by cells and anabolic processes like glycogen, fat and protein synthesis

Question 447

What effect does glucagon have on blood glucose?

Answer 447

Increases it by stimulating protein and fat degradation, glycogenolysis and gluconeogenesis

Question 448

Which three hormones are primarily involved in water homeostasis?

Answer 448

Antidiuretic hormone (ADH or vasopressin), aldosterone and atrial natriuretic peptide (ANP)

Question 449

What releases calcitonin?

Answer 449

Parafollicular (C-) cells of the thyroid

Question 450

Calcitonin

Answer 450

Decreases blood calcium concentration by promoting calcium excretion in the kidneys, decreasing calcium absorption in the gut and promoting calcium storage in bones

Question 451

What releases parathyroid hormone?

Answer 451

Parathyroid glands

Question 452

Parathyroid hormone (PTH)

Answer 452

Increases blood calcium concentration by decreasing calcium excretion by the kidneys and increasing bone resorption
Activates vitamin D
Promotes resorption of phosphate from bone
Reduces phosphate reabsorption in the kidney

Question 453

What releases antidiuretic hormone (ADH or vasopressin)?

Answer 453

The hypothalamus via posterior pituitary

Question 454

Antidiuretic hormone (ADH or vasopressin)

Answer 454

Increases blood volume and decreases blood osmolarity

By increasing reabsorption of water in the collecting duct of the nephron

Question 455

What releases aldosterone?

Answer 455

Adrenal cortex

Question 456

Aldosterone

Answer 456

Increases blood volume with no effect on blood osmolarity by promoting sodium reabsorption in the distal convoluted tubule and collecting duct, thus increasing water reabsorption
Increases potassium and hydrogen ion excretion
Regulated by renin-angiotensin-aldosterone system

Question 457

What releases atrial natriuretic peptide (ANP)?

Answer 457

The heart

Question 458

Atrial natriuretic peptide (ANP)

Answer 458

Decreases blood volume with no effect on blood osmolarity by promoting excretion of salt and water in the kidneys in response to stretching to the atria (high blood volume)

Question 459

Are peptide hormones polar or non-polar?

Answer 459

Polar

Question 460

Can peptide hormone pass through the cell membrane?

Answer 460

No, because they are polar

Question 461

Are steroid hormones polar or non-polar?

Answer 461

Non-polar

Question 462

Can steroid hormones pass through the cell membrane?

Answer 462

Yes, because they are non-polar

Question 463

How do steroid hormones function?

Answer 463

They bind to and promote a conformational change of intracellular or intranuclear receptors; the hormone-receptor complex binds to DNA, affecting the transcription of a particular gene

Question 464

Amino acid-derivative hormones

Answer 464

Modified amino acids

Share some features with peptide hormones and some features with steroid hormones

Question 465

Examples of amino acid-derivative hormones

Answer 465

Epinephrine, norepinephrine, triiodothyronine and thyroxine

Question 466

Do direct hormones affect endocrine or non-endocrine tissues?

Answer 466

Non-endocrine

Question 467

Do tropic hormones affect endocrine or non-endocrine tissues?

Answer 467

Endocrine

Question 468

What is the bridge between the nervous and endocrine systems?

Answer 468

The hypothalamus

Question 469

Negative feedback

Answer 469

The final hormone (or product) of a pathway inhibits hormones (or enzymes) earlier in the pathway, maintaining homeostasis

Question 470

How does the hypothalamus stimulate the anterior pituitary gland?

Answer 470

Through paracrine release of hormones into the hypophyseal portal system, which directly connects the two organs

Question 471

Anterior pituitary hormones

Answer 471

Follicle-stimulating hormone (FSH), luteinizing hormone (LH), adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), prolactin, endorphins and growth hormones

Question 472

Tropic hormones released by the anterior pituitary

Answer 472

FSH, LH, ACTH and TSH

Question 473

Direct hormones released by the anterior pituitary

Answer 473

Prolactin, endorphins and growth hormones

Question 474

Posterior pituitary

Answer 474

Releases two hormones produced in the hypothalamus: Antidiuretic hormone (ADH or vasopressin) and oxytocin

Question 475

What triggers ADH release?

Answer 475

Low blood volume or increased blood osmolarity

Question 476

Oxytocin

Answer 476

Secreted during childbirth and promotes uterine contractions
Promotes milk ejection
Involved in bonding behavior
Has a positive feedback loop

Question 477

Hormones produced by the thyroid

Answer 477

Triiodothyronine (T3), thyroxine (T4) and calcitonin

Question 478

Hormones released by follicular cells

Answer 478

T3 and T4

Question 479

Triiodothyronine (3) and thyroxine (T4)

Answer 479

Contain iodine
Increase metabolic rate
Alter utilization of glucose and fatty acids

Question 480

Vitamin D

Answer 480

Necessary for calcium and phosphate absorption from the gut

Question 481

Adrenal cortex hormones

Answer 481

Cortisol, cortisone, aldosterone, androgens (like testosterone) and estrogen

Question 482

Glucocorticoids released by the adrenal cortex

Answer 482

Cortisol and cortisone

Question 483

Mineralocorticoids released by the adrenal cortex

Answer 483

Aldosterone

Question 484

Cortical sex hormones released by the adrenal cortex

Answer 484

Androgens (like testosterone) and estrogen

Question 485

Cortisol and cortisone

Answer 485

Increase blood glucose concentration
Reduce protein synthesis
Inhibit the immune system
Participate in the stress response
Stimulated by ACTH

Question 486

How is aldosterone regulated?

Answer 486

By the renin-angiotensin-aldosterone system

Question 487

Adrenal medulla hormones

Answer 487

Epinephrine and norepinephrine

Question 488

Epinephrine and norepinephrine

Answer 488

Involved in fight-or-flight response, promote glycogenolysis, increase the basal metabolic rate, increase heart rate, dilate the bronchi and alter blood flow

Question 489

Hormones produced by the pancreas

Answer 489

Glucagon, insulin and somatostatin

Question 490

What produces somatostatin?

Answer 490

Delta-cells of the pancreas

Question 491

Somatostatin

Answer 491

Inhibits insulin and glucagon secretion

Question 492

Pineal gland

Answer 492

Releases melatonin

Question 493

Melatonin

Answer 493

Helps regulate circadian rhythms

Question 494

Hormones produced by the stomach

Answer 494

Secretin, gastrin and cholecystokinin

Question 495

Hormones produced by the kidneys

Answer 495

Erythropoietin

Question 496

Erythropoietin

Answer 496

Stimulate bone marrow to produce erythrocytes in response to low oxygen levels in the blood

Question 497

Hormones secretes by the thymus

Answer 497

Thymosin

Question 498

Thymosin

Answer 498

Important for proper T-cell development and differentiation

Question 499

What releases corticoids?

Answer 499

The adrenal cortex

Question 500

What happens if there is overproduction of growth hormone in children?

Answer 500

Gigantism

Question 501

What happens if there is overproduction of growth hormone in adults?

Answer 501

Acromegaly

Question 502

Acromegaly

Answer 502

Enlargement of the small bones in the extremities and of certain facial bones, such as the jaw

Question 503

What happens if there is a deficiency of growth hormone in children?

Answer 503

Dwarfism

Question 504

Causes of hypothyroidism

Answer 504

Inflammation of the thyroid

Iodine deficiency

Question 505

What happens if a newborn has hypothyroidism?

Answer 505

Cretinism

Question 506

Cretinism

Answer 506

Poor neurological and physical development, including mental retardation, short stature and coarse facial features

Question 507

Goiter

Answer 507

Swelling of the thyroid

Question 508

Causes of hyperthyroidism

Answer 508

Goiter

Question 509

Is oxytocin a peptide or steroid hormone?

Answer 509

Peptide

Question 510

What stimulates somatostatin secretion?

Answer 510

High blood glucose or high blood amino acid levels

Question 511

Is somatostatin inhibitory or excitatory?

Answer 511

Inhibitory

Question 512

What stimulates renin production?

Answer 512

Low blood pressure causes the juxtaglomerular cells of the kidney to produce renin

Question 513

Renin

Answer 513

An enzyme that converts the plasma protein angiotensinogen to angiotensin I

Question 514

Where does angiotensin I convert into angiotensin II?

Answer 514

In the lungs via angiotensin-converting enzymes

Question 515

Angiotensin II

Answer 515

Stimulates the adrenal cortex to secrete aldosterone

Question 516

Is vasopressin a peptide or steroid hormone?

Answer 516

Peptide

Question 517

Respiratory pathway

Answer 517

Nares –> nasal cavity –> pharynx –> larynx –> trachea –> bronchi –> bronchioles –> alveoli

Question 518

Which muscles are involved in inhalation?

Answer 518

Diaphragm and external intercostal muscles

Question 519

Muscles involved in exhalation?

Answer 519

Passive: recoil of diaphragm and external intercostal muscles
Active: internal intercostal muscles and abdomen

Question 520

What is the purpose of surfactant?

Answer 520

Reduces surface tension at the air-liquid interface in the alveoli to prevent their collapse

Question 521

What is the mathematical relationship between vital capacity (VC), inspiratory reserve volume (IRV), expiratory reserve volume (ERV) and tidal volume (TV)?

Answer 521

VC = IRV + ERV + TV

Question 522

If blood levels of CO2 become too low, how does the brain alter the respiratory rate to maintain homeostasis?

Answer 522

Decrease breathing rate

Question 523

What are some of the mechanisms used in the respiratory system to prevent infection?

Answer 523

Immune mechanisms in the respiratory system include vibrissae in the nares, lysosome in the mucous membranes, the mucociliary escalator, macrophages in the lungs, mucosal IgA antibodies and mast cells

Question 524

What is the chemical equation for the bicarbonate buffer system?

Answer 524

CO2 (g) + H2O (l) H2CO3 (aq) H+ (aq) +HCO- (aq)

Question 525

Respiratory failure refers to inadequate ventilation to provide oxygen to the tissues. How would the pH change in respiratory failure?

Answer 525

In respiratory failure, ventilation slows, and less carbon dioxide is blown off. As this occurs, the buffer equation shifts to the right, and more hydrogen ions are generated. This results in a lower pH of the blood.

Question 526

Where does the air inhaled get warmed and humidified?

Answer 526

Nares

Question 527

Vibrissae

Answer 527

Nasal hairs

Question 528

Where does the air inhaled get filtered?

Answer 528

Nasal hairs (vibrissae), mucous membranes and mucocilliary escalator

Question 529

Alveoli

Answer 529

Small sacs that interface with the pulmonary capillaries, allowing gases to diffuse across a one-cell-thick membrane

Question 530

Where is surfactant?

Answer 530

In the alveoli

Question 531

Pleurae

Answer 531

Cover the lungs and line the chest wall

Question 532

Visceral pleura

Answer 532

Lies adjacent to the lung itself

Question 533

Parietal pleura

Answer 533

Lines the chest wall

Question 534

Intrapleural space

Answer 534

Lies between the visceral and partial pleurae and contains a thin later of fluid, which lubricates the two pleural surfaces

Question 535

Diaphragm

Answer 535

A think skeletal muscle that helps to create the pressure differential required for breathing

Question 536

Is inhalation an active or passive process?

Answer 536

Active

Question 537

Inhalation (negative-pressure breathing)

Answer 537

The diaphragm and external intercostal muscles expand the thoracic cavity –> volume of the intrapleural space increases –> pressure of the intrapleural space decreases –> lungs expand –> lung pressure is dropped –> air from the environment enters

Question 538

Is exhalation an active or passive process?

Answer 538

It can be either

Question 539

Passive exhalation

Answer 539

Relaxation of the muscles of inspiration (diaphragm and external intercostal muscles) –> elastic recoil of the lungs –> chest cavity decreases in volume –> pressure differentials seen during inhalation are reversed

Question 540

Active exhalation

Answer 540

Internal intercostal muscles and abdominal muscles are used to forcibly decrease the volume of the thoracic cavity –> air is pushed out

Question 541

Spirometer

Answer 541

Measures lung capacities and volumes

Question 542

Total lung capacity (TLC)

Answer 542

The maximum volume of air in the lungs when one inhales completely

Question 543

Residual volume (RV)

Answer 543

The minimum volume of air in the lungs when one exhales completely

Question 544

Vital capacity (VC)

Answer 544

The difference between the minimum and maximum volume of air in the lungs

Question 545

Tidal volume (TV)

Answer 545

The volume of air inhaled or exhaled in a normal breath

Question 546

Expiratory reserve volume (ERV)

Answer 546

The volume of additional air that can be forcibly exhaled after a normal exhalation

Question 547

Inspiratory reserve volume (IRV)

Answer 547

The volume of additional air that can be forcibly inhaled after a normal inhalation

Question 548

Ventilation center

Answer 548

Regulated ventilation

A collection of neurons in the medulla oblongata

Question 549

Chemoreceptors

Answer 549

Respond to carbon dioxide concentrations, increasing the respiratory rate when there are high concentrations of carbon dioxide in the blood

Question 550

Hypercarbia

Answer 550

High carbon dioxide concentrations in the blood

Question 551

Hypercapnia

Answer 551

High carbon dioxide concentrations in the blood

Question 552

How does the ventilation center respond to low oxygen concentrations in the blood?

Answer 552

Increasing breathing rate

Question 553

Hypoxemia

Answer 553

Low oxygen concentrations in the blood

Question 554

How can ventilation be consciously controlled?

Answer 554

With the cerebrum (although the medulla oblongata will override the cerebrum during extended periods of hypo- or hyperventilation)

Question 555

How do lungs perform gas exchange with the blood?

Answer 555

Simple diffusion across concentration gradients

Question 556

Pulmonary arteries

Answer 556

Carry deoxygenated blood with high carbon dioxide concentration to the lungs

Question 557

Pulmonary veins

Answer 557

Carry oxygenated blood with low carbon dioxide concentration away from the lungs

Question 558

How do lungs participated in thermoregulation?

Answer 558

The large surface area of interaction between the alveoli and capillaries allows the respiratory system to assist in thermoregulation through vasodilation and vasoconstriction of capillary beds

Question 559

How do lysozyme in the nasal cavity and saliva protect the respiratory system?

Answer 559

Attack peptidoglycan cell walls of gram-positive bacteria

Question 560

How do macrophages protect the respiratory system?

Answer 560

They engulf and digest pathogens and signal to the rest of the immune system that there is an invader

Question 561

What are mucosal surfaces covered with?

Answer 561

IgA antibodies

Question 562

How do mast cells protect the respiratory system?

Answer 562

They have antibodies on their surface that, when triggered, can promote the release of inflammatory chemicals
Involved in allergic reactions

Question 563

How is the respiratory system involved in pH control?

Answer 563

Through the bicarbonate buffer system

Question 564

How does the respiratory system control pH when blood pH decreases?

Answer 564

Respiration rate increases to compensate by blowing off carbon dioxide. This causes a left shift in the buffer equation, reducing hydrogen ion concentration.

Question 565

How does the respiratory system control pH when blood pH increases?

Answer 565

Respiration rate decreases to compensate by trapping carbon dioxide. This causes a right shift in the buffer equation, increasing hydrogen ion concentration.

Question 566

Total lung capacity (TLC)

Answer 566

= VC (vital capacity) + RV (residual volume)

Question 567

What can introducing fluid or air to the intrapleural space do?

Answer 567

Collapse the lung

Question 568

Epiglottis

Answer 568

Covers the glottis during swelling to ensure that no food enters the trachea

Question 569

Are the trachea and bronchi lined by ciliated epithelial cells?

Answer 569

Yes

Question 570

Where are the vocal cords?

Answer 570

Larynx

Question 571

What happens if the lungs become stiff?

Answer 571

Inspiratory reserve volume decreases

Question 572

Hyperventilation

Answer 572

Decreases blood carbon dioxide concentration

Question 573

Positive end-expiratory pressure

Answer 573

Providing a higher pressure than normal at the end of expiration, forcing extra air into the alveoli to prevent alveolar collapse

Question 574

Heart chambers

Answer 574

Right atrium, right ventricle, left atrium, left ventricle

Question 575

Which valve prevents back flow to the right atrium?

Answer 575

Tricuspid valve (between right atrium and right ventricle)

Question 576

Which valve prevents back flow to the right ventricle?

Answer 576

Pulmonary valve (between right ventricle and pulmonary artery)

Question 577

Which valve prevents back flow to the left atrium?

Answer 577

Mitral (bicuspid valve) (between left atrium and left ventricle)

Question 578

Which valve prevents back flow to the left ventricle?

Answer 578

Aortic valve (between left ventricle and aortic artery)

Question 579

Structures in the conduction system of the heart

Answer 579

Sinoatrial node (SA node) –> atrioventricular node (AV node) –> bundle of His (AV bundle) and its branches –> Purkinje fibers

Question 580

In which direction do arteries carry blood?

Answer 580

Away from the heart

Question 581

In which direction do capillaries carry blood?

Answer 581

From arterioles to venules

Question 582

In which direction do veins carry blood?

Answer 582

Towards the heart

Question 583

Are arteries thick or thin?

Answer 583

Thick

Question 584

Are capillaries thick or thin?

Answer 584

Very thin (one cell layer)

Question 585

Are veins thick or thin?

Answer 585

Thin

Question 586

Do arteries have smooth muscles?

Answer 586

Yes (a lot)

Question 587

Do capillaries have smooth muscles?

Answer 587

No

Question 588

Do veins have smooth muscles?

Answer 588

Yes (a little)

Question 589

Do arteries have valves?

Answer 589

No

Question 590

Do capillaries have valves?

Answer 590

No

Question 591

Do veins have valves?

Answer 591

Yes

Question 592

Why does the right side of the heart contain less cardiac muscle than the left side?

Answer 592

The right side of the heart pumps blood into a lower-resistance circuit and must do so at lower pressure; therefore, it requires less muscle. The left side of the heart pumps blood into a higher-resistance circuit at higher pressures; therefore, it requires more muscle.

The left side of the heart contains more muscle than the right side because the systemic circulation has a much higher resistance and pressure.

Question 593

If all autonomic input to the heart were cut, what would happen?

Answer 593

The heart would continue beating at the intrinsic rate of the pacemaker (SA node). The individual would be unable to change his or her heart rate via the sympathetic or parasympathetic nervous system, but the heart would not stop beating.

Question 594

Components of plasma

Answer 594

Nutrients, salts, respiratory gases, hormones and blood proteins (clotting proteins, immunoglobulin, etc.)

Question 595

Hematocrit

Answer 595

The percentage of a blood sample occupied by red blood cells

Question 596

Hematocrit units

Answer 596

Percentage points

Question 597

Which types of leukocytes are involved in the specific immune response?

Answer 597

Lymphocytes

Question 598

Where do platelets come from?

Answer 598

Megakaryocytes in the bone marrow

Question 599

Which cell types in blood contain a nucleus?

Answer 599

Leukocytes (including neutrophils, eosinophils, basophils, monocytes/macrophages and lymphocytes)

Question 600

Which cell types in blood do not contain a nucleus?

Answer 600

Erythrocytes and platelets

Question 601

Platelets

Answer 601

Cellular fragments or shards

Question 602

In bacterial sepsis (overwhelming bloodstream infection), a number of capillary beds throughout the body open simultaneously. What effect would this have on the blood pressure? Besides the risk of infection, why might sepsis be dangerous for the heart?

Answer 602

Opening up more capillary beds (which are in parallel) will decrease the overall resistance of the circuit. The cardiac output will therefore increase in an attempt to maintain constant blood pressure. This is a risk to the heart because the increased demand on the heart can eventually tire it, leading to a heart attack or a precipitous drop in blood pressure.

Question 603

What is the chemical equation for the bicarbonate buffer system?

Answer 603

CO2 (g) + H2O (l) H2CO3 (aq) H+ (aq) + HCO3- (aq)

Question 604

What enzyme catalyzes the bicarbonate buffer system?

Answer 604

The combining of carb on dioxide and water is catalyzed by carbonic anhydrase

Question 605

Where should you look on the oxyhemoglobin dissociation curve to determine the amount of oxygen that has been delivered to tissues?

Answer 605

The amount of oxygen deliver can be seen as a drop in the y-value (percent hemoglobin saturation) on an oxyhemoglobin dissociation curve.

E.g. if the blood is 100% saturated while in the lungs (at 100 mmHg O2) and only 80% saturated while in the tissues (40 mmHg O2), then 20% of the oxygen has been released to tissues.

Question 606

What can cause a right shift of the oxyhemoglobin dissociation curve?

Answer 606

Increased CO2
Increased [H+] (i.e. decreased pH)
Increased temperature
Increased 2,3-BPG

Question 607

What can cause a left shift of the oxyhemoglobin dissociation curve?

Answer 607

Decreased CO2
Decreased [H+] (i.e. increased pH)
Decreased temperature
Decreased 2,3-BPG

Question 608

Exposure of which subendothelial compounds start the coagulation cascade?

Answer 608

Collagen and tissue factor

Question 609

Which protein helps stabilize the clot formed by the coagulation cascade?

Answer 609

Fibrin

Question 610

Cardiac output (CO)

Answer 610

= HR x SV = heart rate x stroke volume

Question 611

Ohm’s law applied to circulation

Answer 611

delta P = CO x TPR

Question 612

Cardiovascular system

Answer 612

Consists of a muscular four-chambered heart, blood vessels and blood

Question 613

What kind of muscle composes the heart?

Answer 613

Cardiac muscle

Question 614

What kind of circulation is supported by the heart?

Answer 614

Pulmonary circulation and systemic circulation

Question 615

Atrioventricular valves

Answer 615

Separate the atria from the ventricles

Tricuspid (right heart)
Mitral (bicuspid) (left heart)

Question 616

Where is the tricuspid valve?

Answer 616

Between the right atrium and the right ventricle

Question 617

Where is the mitral (bicuspid) valve?

Answer 617

Between the left atrium and the left ventricle

Question 618

How are the ventricles separated from the vasculature?

Answer 618

Semilunar valves

Pulmonary (right heart)
Aortic (left heart)

Question 619

Where is the pulmonary valve?

Answer 619

Between the right ventricle and the pulmonary artery

Question 620

Where is the aortic valve?

Answer 620

Between the left ventricle and the aortic artery

Question 621

Pathway of blood

Answer 621

Right atrium –(tricuspid valve)–> right ventricle –(pulmonary valve)–> pulmonary artery –> lungs –> pulmonary veins –> left atrium –(mitral valve)–> left ventricle –(aortic valve)–> aorta –> arteries –> arterioles –> capillaries –> venules –> veins –> venae cavae –> right atrium

Question 622

Systole

Answer 622

The period during ventricular contraction when the AV valves are closed

Question 623

Diastole

Answer 623

The heart is relaxed and the semilunar valves are closed

Question 624

Arteries

Answer 624

Thick, highly muscular structures with an elastic quality

Question 625

Why is it important for arteries to have an elastic quality?

Answer 625

For recoil and propelling blood forward within the system

Question 626

Arterioles

Answer 626

Small muscular arteries that control flow into the capillary beds
Have the ability to contract and dilate in order to affect blood pressure

Question 627

Capillaries

Answer 627

Have walls that are one cell thick

They are the sites of gas and solute exchange

Question 628

Why is it important for capillaries to have one-cell thick walls?

Answer 628

It makes them narrow enough that red blood cells can travel through them in single-file lines

Question 629

Veins

Answer 629

Inelastic, thin-walled structures that transport blood to the heart
They are able to stretch, but they cannot recoil
Have valves

Question 630

Why is it important for veins to be able to stretch?

Answer 630

To accommodate large volumes of blood

Question 631

Since veins are able to stretch but cannot recoil, how are veins compressed?

Answer 631

By the surrounding skeletal muscles

Question 632

Why is it important for veins to have valves?

Answer 632

To maintain one-way flow in the system

Question 633

Venules

Answer 633

Small veins

Question 634

Portal system

Answer 634

Blood passes through two capillary beds in series

Question 635

Hepatic portal system

Answer 635

Blood travels from the gut capillary beds to the liver capillary bed via the hepatic portal vein

Question 636

Hypophyseal portal system

Answer 636

Blood travels form the hypothalamus to the anterior pituitary

Question 637

Renal portal system

Answer 637

Blood travels form the glomerulus to the vasa recta through an efferent arteriole

Question 638

Erythrocytes (red blood cells)

Answer 638

Lack mitochondria, a nucleus and organelles

Question 639

Why is it that erythrocytes lack mitochondria, a nucleus and organelles?

Answer 639

To make room for hemoglobin

Question 640

Hemoglobin

Answer 640

A protein that carries oxygen

Question 641

Leukocytes (white blood cells)

Answer 641

Partake in the immune system

Question 642

Where are leukocytes (WBCs) formed?

Answer 642

In the bone marrow

Question 643

Types of leukocytes

Answer 643

Granular leukocytes and agranulocytes

Question 644

Granular leukocytes

Answer 644

Act in nonspecific immunity

Neutrophils, eosinophils, basophils

Question 645

Agranulocytes

Answer 645

Act in specific immunity

Lymphocytes and monocytes

Question 646

Thrombocytes (platelets)

Answer 646

Cell gradients from megakaryocytic that are required for coagulation

Question 647

Blood antigens

Answer 647

A, B, O, Rh factor (D)

Question 648

What is the relationship between I^A (A), I^B (B) and i (O)?

Answer 648

I^A (A) and I^B (B) are codominant

I (O) is recessive

Question 649

Does an individual have ABO antibodies for ABO allele he or she has or does not have?

Answer 649

Does not have

Question 650

Is positive Rh factor a dominant or recessive trait?

Answer 650

Dominant

Question 651

What kind of antibodies would an Rh-negative individual create?

Answer 651

Anti-Rh antibodies, but only after exposure to Rh-positive blood

Question 652

Blood pressure

Answer 652

The force per unit area that is exerted on the walls of blood vessels by blood

Divided into systolic and diastolic components

It must be high enough to overcome the resistance created by arterioles and capillaries, but low enough to avoid damaging the vasculature and surrounding structures

Question 653

How is blood pressure measured?

Answer 653

With a sphygmomanometer

Question 654

How is blood pressure maintained?

Answer 654

By baroreceptor and chemoreceptor reflexes

Question 655

Hormones released when blood pressure is low

Answer 655

Aldosterone and antidiuretic hormone (ADH or vasopressin)

Question 656

Hormones released when blood osmolarity is high

Answer 656

ADH (antidiuretic hormone or vasopressin)

Question 657

Hormones released when blood pressure is high

Answer 657

Atrial natriuretic peptide (ANP)

Question 658

Where does gas and solute exchange occur?

Answer 658

At the capillaries

Question 659

What does gas and solute exchange rely on?

Answer 659

Concentration gradients to facilitate diffusion across the capillary walls

Question 660

Are capillaries leaky?

Answer 660

Yes, which aids in transport of gases and solutes

Question 661

Starling forces

Answer 661

Consist of hydrostatic pressure and osmotic (oncotic) pressure

Question 662

Hydrostatic pressure

Answer 662

The pressure of the fluid within the blood vessel

Forces fluid out at the arteriolar end of a capillary bed

Question 663

Osmotic pressure

Answer 663

The sucking pressure drawing water towards solutes

Question 664

Oncotic pressure

Answer 664

Osmotic pressure due to proteins

Draws fluid back into the capsular bed at the venue end

Question 665

Does hemoglobin exhibit cooperative binding?

Answer 665

Yes

Question 666

Is there a high or low partial pressure of oxygen in the lungs?

Answer 666

High

Question 667

Why is it important for the lungs to have high partial pressure of oxygen?

Answer 667

To promote the loading of oxygen onto hemoglobin

Question 668

Is there a high or low partial pressure of oxygen in the tissues?

Answer 668

Low

Question 669

Why is it important for the tissues to have low partial pressure of oxygen?

Answer 669

To promote the unloading of oxygen

Question 670

Why is it important for hemoglobin to exhibit cooperative binging?

Answer 670

With each successive oxygen bound to hemoglobin, the affinity of the other subunits to oxygen increases. With each successive oxygen release from hemoglobin, the affinity of the other subunits to oxygen decreases.

Question 671

How is carbon dioxide carried in the blood?

Answer 671

In the form of carbonic acid or bicarbonate and hydrogen ions

Question 672

Why does carbon dioxide travel in the blood in the form of carbonic acid or bicarbonate and hydrogen ions?

Answer 672

Carbon dioxide is non polar and not particularly soluble, while bicarbonate, hydrogen ions and carbonic acid are polar and highly soluble

Question 673

What does a right shift in the oxyhemoglobin dissociation curve mean?

Answer 673

Decreased affinity for oxygen

Question 674

What does a left shift in the oxyhemoglobin dissociation curve mean?

Answer 674

Increased affinity for oxygen

Question 675

Where can a left shift in the oxyhemoglobin dissociated curve be seen?

Answer 675

The lungs and in fetal hemoglobin

Question 676

Coagulation

Answer 676

Results from an activation cascade

Endothelial lining of a blood vessel is damaged –> collagen and tissue factor underlying the endothelial cells are exposed –> Coagulation cascade is activated –> Blood clot forms over the damaged area

Question 677

What is fibrin activated by?

Answer 677

Thrombin

Question 678

How can clots be broken down?

Answer 678

By plasmin

Question 679

Are erythrocytes aerobic or anaerobic?

Answer 679

Anaerobic

Question 680

Where are erythrocytes phagocytized?

Answer 680

In the spleen and liver

Question 681

Where are erythrocytes produced?

Answer 681

In the red bone marrow

Question 682

How long do erythrocytes circulated in the blood?

Answer 682

For 120 days

Question 683

What is the correct sequence of a cardiac impulse?

Answer 683

SA node –> atria –> AV node –> bundle of His –> Purkinje fibers –> ventricles

Question 684

How does the osmotic pressure relate to the hydrostatic pressure at the venous end of a capillary bed?

Answer 684

It is greater than the hydrostatic pressure

Question 685

How does the osmotic (oncotic) pressure change in a capillary end from the arterial end to the venous end?

Answer 685

It doesn’t

Question 686

How does the hydrostatic pressure change in a capillary end from the arterial end to the venous end?

Answer 686

It decreases from the arterial end to the venous end

Question 687

Do proteins normally cross the capillary wall?

Answer 687

No

Question 688

How is pressure in the aorta related to pressure in the superior vena cava?

Answer 688

It is always higher than the pressure in the superior vena cava

Question 689

Due to kidney disease, a person is losing albumin into the urine. What effect is this likely to have within the capillaries?

Answer 689

Decreased oncotic pressure

Question 690

What generates osmotic (oncotic) pressure?

Answer 690

Plasma proteins

Question 691

The world record for the longest-held breath is 22 minutes and 0 seconds. If a sample were taken from this individual during the last minute of breath-holding, which of the following might be observed?

Answer 691

Decreased pH

Holding one’s breath for a prolonged period would result in a drop of oxygenation and an increase in pCO2. The increased carbon dioxide would associate with water to form carbonic acid, which would dissociate into a proton and bicarbonate anion. Further, the low oxygen saturation would eventually lead to anaerobic metabolism in some tissues, causing an increase in lactic acid. These would all lead to a decreased pH

Question 692

A person has a heart attack that primarily affects the wall between the two ventricles. Which portion of the electrical conduction system is most likely affected?

Answer 692

Bundle of His

Question 693

Which vascular structure creates the most resistance to blood flow?

Answer 693

Arterioles

Question 694

Which vascular structure creates the greatest drop in blood pressure?

Answer 694

Arterioles

Question 695

Innate (nonspecific) immunity

Answer 695

Consists of defenses that are always active against pathogens, but that are not capable of targeting specific invaders and cannot maintain immunologic memory

Question 696

Adaptive (specific) immunity

Answer 696

Response targets a specific pathogen and maintains immunologic memory of the infection to mount a faster response during subsequent infections

Question 697

Site of B-cell development

Answer 697

Bone marrow

Question 698

Site of T-cell development

Answer 698

Bone marrow

Question 699

Site of B-cell maturation

Answer 699

Bone marrow (but are activated in the spleen or lymph nodes)

Question 700

Site of T-cell maturation

Answer 700

Thymus

Question 701

Major functions of B-cells

Answer 701

Produce antibodies

Question 702

Major functions of T-cells

Answer 702

Coordinate immune system and directly kill infected cells

Question 703

Are B-cells specific or nonspecific?

Answer 703

Specific

Question 704

Are T-cells specific or nonspecific?

Answer 704

Specific

Question 705

Are B-cells humoral or cell-mediated?

Answer 705

Humoral

Question 706

Are T-cells humoral or cell-mediated?

Answer 706

Cell-mediated

Question 707

Which cells are considered granulocytes?

Answer 707

Neutrophils, eosinophils, basophils and mast cells

Question 708

Which cells are considered agranulocytes?

Answer 708

Lymphocytes (B-cells and T-cells) and macrophages (monocytes)

Question 709

Is innate immune faster or slowed than adaptive immunity?

Answer 709

Faster

Question 710

Site of B-cell activation

Answer 710

Spleen or lymph nodes

Question 711

What is the immunologic function of skin?

Answer 711

Physical barrier

Secretion of antimicrobial enzymes

Question 712

What is the immunologic function of defensins?

Answer 712

Antibacterial enzymes on the skin

Question 713

What is the immunologic function of lysozyme?

Answer 713

Antimicrobial

Present in tears and saliva

Question 714

What is the immunologic function of mucus?

Answer 714

Present on mucous membranes

Traps incoming pathogens (in the respiratory system, cilia propel the mucus upward so it can be swallowed or expelled)

Question 715

What is the immunologic function of stomach acid?

Answer 715

Antimicrobial

Question 716

What is the immunologic function of normal gastrointestinal flora?

Answer 716

Provides competition, making it hard for pathogenic bacteria to grow in the gut

Question 717

What is the immunologic function of complement?

Answer 717

A set of proteins in the blood that can create holes in bacteria

Question 718

Which cells are professional antigen-presenting cells?

Answer 718

Macrophages, dendritic cells in the skin, some B-cells and certain activated epithelial cells

Question 719

MHC-I

Answer 719

Found in all nucleated cells and presents proteins created within the cell (endogenous antigens); this can allow for detection of cells infected with intracellular pathogens (especially viruses)

Question 720

MHC-II

Answer 720

Only found in antigen-presenting cells and presents proteins that result from the digestion of extracellular pathogens that have been brought in by endocytosis (exogenous antigens)

Question 721

What activates natural killer cells?

Answer 721

Cells that do not present MHC (such as virally infected cells and cancer cells)

Question 722

What activates neutrophils?

Answer 722

Bacteria, especially those that have been opsonized (tagged with an antibody on their surface)

Question 723

What activates eosinophils?

Answer 723

Invasive parasites and allergens

Question 724

What activates basophils?

Answer 724

Allergens

Question 725

What activates mast cells?

Answer 725

Allergens

Question 726

Where are defensins?

Answer 726

On the skin

Question 727

Where are lysozymes?

Answer 727

In tears and saliva

Question 728

Where are mucosa?

Answer 728

On mucous membranes

Question 729

Where are complements?

Answer 729

In the blood

Question 730

Where is MHC-I?

Answer 730

On all nucleated cells

Question 731

Where is MHC-II?

Answer 731

On antigen-presenting cells

Question 732

Opsonization

Answer 732

Mark a pathogen for destruction by phagocytic cells

Question 733

Plasma cell

Answer 733

Form from B-cells exposed to antigen and produce antibodies

Question 734

Memory B-cell

Answer 734

Form from B-cells exposed to antigen and lie in wait for a second exposure to a I=given antigen to be able to mount a rapid, robust response

Question 735

Helper T-cell (CD4+ cells)

Answer 735

Coordinate the immune system through lumphokines and respond to antigen bound to MHC-II

Question 736

Cytotoxic T-cell (CD8+ cells)

Answer 736

Directly kill virally infected cells and response to antigen bound to MHC-I

Question 737

Suppressor (regulatory) T-cell

Answer 737

Quell the immune response after a pathogen has been cleared and promote self-tolerance

Question 738

Memory T-cell

Answer 738

Lie in wait until a second exposure to a pathogen to be able to mount a rapid, robust response

Question 739

What are the three main effects circulating antibodies can have on a pathogen?

Answer 739

Opsonization, causing angulation of the pathogen in insoluble complexes that can be taken up by phagocytic cells, or neutralize the pathogen by preventing its ability to invade tissues

Question 740

How do antibodies become specific for a given antigen?

Answer 740

B-cells originally mature in the bone marrow and have some specificity at that point; however, antibodies that can respond to a given antigen undergo hypermutation, or rapid mutation of their antigen-binding sites. Only those B-cells that have the highest affinity for the antigen survive and proliferate, increasing the specificity for the antigen over time.

Question 741

Positive selection

Answer 741

Occurs when T-cells in the thymus that are able to respond to antigen presented on MHC are allowed to survive (those that do not respond undergo apoptosis)

Question 742

Negative selection

Answer 742

Occurs when T-cells that respond to self-antigens undergo apoptosis before leaving the thymus

Question 743

Which cells account for the fact that the secondary response to a pathogen is much more rapid and robust than the primary response?

Answer 743

Memory cells

Question 744

Active immunity

Answer 744

The stimulation of the immune system (activation of B-cells) to produce antibodies against a pathogen

Question 745

Passive immunity

Answer 745

The transfer of antibodies to prevent infection, without stimulation of the plasma cells that produce these antibodies

Question 746

Filariasis is the name for an infection with a certain group of parasites, most notable Wuchereria bancrofti. This parasite resides in lymph nodes and causes blockage of flow. If an individual had W. bancrofti infection in the lymph nodes of his or her thigh, what would likely happen?

Answer 746

Fluid would be unable to return from the lower leg, and edema would result. This infection leads to elephantiasis, severe swelling of the limb with thickening of the skin.

Question 747

What structure is primarily responsible for returning material from lymphatic circulation to the cardiovascular system?

Answer 747

The thoracic duct carries lymphatic fluid into the left subclavian vein

Question 748

The immune system divisions

Answer 748

Innate immunity

Adaptive immunity

Question 749

Where do immune cells come from?

Answer 749

Bone marrow

Question 750

Where are immune responses mounted?

Answer 750

Spleen and lymph nodes

Question 751

Gut-associated lymphoid tissue (GALT)

Answer 751

Tonsils and adenoids

Question 752

Nonspecific (innate) noncellular defenses

Answer 752

Skin, defensins, mucous, lysozyme, stomach acid, colonization of the gut (i.e. flora), complement, interferons

Question 753

Interferons

Answer 753

Given off by virally infected cells and help prevent viral replication and dispersion to nearby cells

Question 754

Nonspecific (innate) cellular defenses

Answer 754

Macrophages, MHC-I, MHC-II, dendritic cells, natural killer cells, granulocytes (neutrophils, eosinophils, basophils, and mast cells)

Question 755

Macrophages

Answer 755

Ingest bathoses and present them on major histocompatibility complex (MHC)
Secrete cytokines

Question 756

Dendritic cells

Answer 756

Antigen presenting cells in the skin

Question 757

Where are dendritic cells?

Answer 757

In the skin

Question 758

Natural killer cells

Answer 758

Attack cells not presenting MHC molecules, including virally infection cells and cancer cells

Question 759

Neutrophils

Answer 759

Ingest bacteria, particularly opsonized bacteria

Can follow bacteria using chemotaxis

Question 760

How do neutrophils follow bacteria?

Answer 760

Chemotaxis

Question 761

Eosinophils

Answer 761

Usual in allergic reactions and invasive parasitic infections
Releases histamine, causing an inflammatory response

Question 762

Basophils

Answer 762

Used in allergic reactions

Question 763

Mast cells

Answer 763

Used in allergic reactions

Found in the skin

Question 764

Where are mast cells?

Answer 764

In the skin

Question 765

Humoral identity

Answer 765

Centered on antibody production by plasma cells, which are activated by B-cells

Question 766

How are plasma cells activated?

Answer 766

By B-cells

Question 767

Antibodies

Answer 767

Target a particular antigen
Contain two heavy chains and two light chains
Have a constant region and variable region
The tip of the variable region is the antigen-binding region

Question 768

What happens when an antibody is activated?

Answer 768

The antigen-binding region undergoes hypermutation to improve the specificity of the antibody produced
Cells may be given signals to switch isotopes of antibody (IgM, IgD, IgG, IgE, IgA)

Question 769

What do cell-surface antibodies do?

Answer 769

Activate immune cells or mediate allergic reactions

Question 770

Humoral immunity activation

Answer 770

Antibodies bind to antigens –> hypermutation in the antigen-binding region occurs –> antibody-antigen complex response (opsonization, aggulation or neutralization) –> immune response activated or allergic reaction activated –> Memory B-cells wait for second exposure in order to become more rapid

Question 771

Cell-mediated (cytotoxic) immunity

Answer 771

Centered on the functions of T-cells

T-cells undergo maturation in thymus through positive selection and negative selection –> the peptide hormone thyroxine promotes T-cell development –> helper T-cells respond to antigen on MHC-II and coordinate the rest of the immune response, secreting lymphokines to activate various arms of immune defense –> Th1 cells secrete interferon gamma, which acerbates macrophages –> Th2 cells activate B-cells, primarily in parasitic infections –> cytotoxic T-cells (Tc, CTL, CD8+) respond to antigen on MHC-I and kill virally infected cells –> suppressor (regulatory) T-cells (Treg) tone down the immune response after an infection and promote self-tolerance

Question 772

Autoimmune conditions

Answer 772

A self-antigen is recognized as foreign, and the immune system attacks normal cells

Question 773

Allergic reactions

Answer 773

Nonthreatening exposures incite an inflammatory response

Question 774

What form of immunity is immunization?

Answer 774

Active immunity

Question 775

Lymphatic system

Answer 775

A circulatory system that consists of one-way vessels with intermittent lymph nodes
Equalizes fluid distribution, transports fats and fat-soluble compounds in chylomicrons and provides sites for mounting immune responses

Question 776

How does the lymphatic system connect to the cardiovascular system?

Answer 776

Thoracic duct in the posterior chest

Question 777

In DiGeorge syndrome, the thymus can be completely absent. The absence of the thymus would leave an individual unable to mount specific defenses against which of the following types of pathogens?

Answer 777

Viruses

T-lymphocytes, which mature in the thymus, are the only specific defense against intracellular pathogens.

Question 778

Where are most self-reactive T-cells eliminated?

Answer 778

Thymus

Question 779

What is the response of the immune system to down regulation of MHC molecules on somatic cells?

Answer 779

Natural killer cells induce apoptosis of affected cells

Healthy cells exhibit MHC-I molecules. Natural killer cells monitor the expression of MHC molecules on the forces of cells. Viral infection and cancer often cause a reduction in the expression of MHC-I molecules on the cell surface. Natural killer cells detect this lack of MHC and induce apoptosis in the affected cells

Question 780

What happens when CD8+ T-cells are activated?

Answer 780

Cytotoxic chemicals are secreted

Question 781

Lymphoma is cancer of the cells of the lymphoid lineage. These cells often reside within lymph nodes. What type of cell is not likely to cause a lymphoma?

Answer 781

Any cell that is not in the B-cell or T-cell lineages

Question 782

Clonal selection

Answer 782

When the adaptive immune system encounters an antigen, only the cells with receptors (antibodies or T-cell receptors) specific to that antigen are activated

Question 783

Which cell type is a phagocyte that attacks bacterial pathogens in the bloodstream?

Answer 783

Neutrophils

Dendritic cells also have a similar function, but they exist in the skin, not the bloodstream

Question 784

What type of immunity is likely to be affected by removal of the spleen?

Answer 784

Humoral immunity because it’s where B-cells mature and proliferate

Question 785

Mechanical digestion

Answer 785

Physically breaks food into smaller pieces

e.g. chewing

Question 786

Chemical digestion

Answer 786

Involves hydrolysis of bonds and breakdown of food into smaller biomolecules

Question 787

Path of food through the body

Answer 787

Oral cavity (mouth) –> pharynx –> esophagus –> stomach –> small intestine –> large intestine –> rectum –> anus

Question 788

What effect does the parasympathetic nervous system have on the digestive system?

Answer 788

Increases secretion from all of the glands of the digestive system and promotes peristalsis

Question 789

What effect does the sympathetic nervous system have on the digestive system?

Answer 789

Decreases secretion from all of the glands of the digestive system and slows peristalsis

Question 790

What two main enzymes are found in the saliva?

Answer 790

Salivary amylase (ptyalin) and lipase

Question 791

What does the mucous cell secrete?

Answer 791

Mucus (rich in bicarbonate)

Question 792

What does the chief cell secrete?

Answer 792

Pepsinogen

Question 793

What does the parietal cell secrete?

Answer 793

HCl and intrinsic factor

Question 794

What does the G-cell secrete?

Answer 794

Gastrin

Question 795

What does the mucous cell do?

Answer 795

Protects lining of stomach
Increases pH (bicarbonate)

Question 796

What does the chief cell do?

Answer 796

Digests proteins once activated by H+

Question 797

What does the parietal cell do?

Answer 797

HCl: decreases pH, kills microbes, denatures proteins, some chemical digestion
Intrinsic factor: absorption of vitamin B12

Question 798

What does the G-cell do?

Answer 798

Increases HCl production

Increases gastric motility

Question 799

Is sucrase an enzyme or a hormone?

Answer 799

Enzyme

Question 800

Is secretin an enzyme or a hormone?

Answer 800

Hormone

Question 801

Is Dipeptidase an enzyme or a hormone?

Answer 801

Enzyme

Question 802

Is cholecystokinin an enzyme or a hormone?

Answer 802

Hormone

Question 803

Is enteropeptidase an enzyme or a hormone?

Answer 803

Enzyme

Question 804

What does sucrase do?

Answer 804

Brush-border enzyme

Breaks down sucrose (a disaccharide) into monosaccharides (glucose and fructose)

Question 805

What does secretin do?

Answer 805

Increases pancreatic secretions into the digestive tract, especially bicarbonate
Reduces HCl secretion
Decreases motility

Question 806

What does dipeptidase do?

Answer 806

Brush-border enzyme

Breaks down dipeptides into free amino acids

Question 807

What does cholecystokinin do?

Answer 807

Recruits secretions from gallbladder and pancreas

Promotes satiety

Question 808

What does enteropeptidase do?

Answer 808

Activates trypsinogen and procarboxypeptidases, which initiates an activation cascade

Question 809

How do bile and pancreatic lipase work together to digest fats?

Answer 809

Bile accomplishes mechanical digestion of fats, emulsifying them and increasing their surface area. Pancreatic lipase accomplishes chemical digestion of fats, breaking their ester bonds.

Question 810

Salivary amylase (ptyalin)

Answer 810

Digests starch into smaller sugars (maltose and dextrin)

Question 811

Lipase

Answer 811

Digests fats

Question 812

Which pancreatic enzyme(s) can digest carbohydrates?

Answer 812

Pancreatic amylase

Question 813

Which pancreatic enzyme(s) can digest proteins?

Answer 813

Trypsin, chymotrypsin, carboxypeptidases A and B

Question 814

Which pancreatic enzyme(s) can digest fats?

Answer 814

Pancreatic lipase

Question 815

What are the main components of bile?

Answer 815

Bile salts (amphipathic molecules derived from cholesterol that emulsify fats), piglets (especially bilirubin from the breakdown of hemoglobin) and cholesterol

Question 816

Where is bile synthesized?

Answer 816

Liver

Question 817

Where is bile stored?

Answer 817

gallbladder

Question 818

Where does bile carry out its digestive function?

Answer 818

Duodenum

Question 819

Functions of the liver

Answer 819

Process nutrients (through glycogenesis and glycogenolysis, storage and mobilization of fats and gluconeogenesis)
Produces urea
Detoxifies chemicals
Activates or inactivates medications
Produces bile
Synthesizes albumin and clotting factor

Question 820

The accessory organs of digestion originate from which primary germ layer?

Answer 820

Endoderm

Question 821

Bile salts

Answer 821

Amphipathic molecules derived from cholesterol that emulsify fats

Question 822

How does the liver process nutrients?

Answer 822

Glycogenesis
Glycohenolysis
Storage and mobilization of fats
Gluconeogenesis

Question 823

What are the two circulatory vessels in a villus?

Answer 823

Capillaries and lacteals

Question 824

What are the four fat-soluble vitamins?

Answer 824

Vitamins A, D, E, K

Question 825

What are the three sections of the small intestine?

Answer 825

Duodenum, jejunum and ileum

Question 826

What are the three sections of the large intestine?

Answer 826

Cecum, colon and rectum

Question 827

Vibrio cholera causes a severe infection in the intestines, leading to massive volumes of watery diarrhea - up to 20 liters per day. Given these symptoms, Dows cholera likely impose the small intestine or the large intestine?

Answer 827

While the large intestine’s main function is to absorb water, the small intestine actually absorbed a much larger volume of water. This, massive volumes of watery diarrhea are more likely to arise from infections in the small intestine than the large intestine.

Question 828

What do the capillaries in a villus absorb?

Answer 828

Water-soluble nutrients

e.g. monosaccharides, amino acids, small fatty acids, water-soluble vitamins and water

Question 829

What do the lacteals in a villus absorb?

Answer 829

Fat-soluble nutrients

e.g. fats, cholesterol and dat-soluble vitamins

Question 830

Intracellular digestion

Answer 830

Involves the oxidation of glucose and fatty acids to make energy

Question 831

Extracellular digestion

Answer 831

Occurs in the lumen of the alimentary canal

Question 832

Accessory organs of digestion

Answer 832

Salivary glands, pancreas, liver and gallbladder

Question 833

Enteric nervous system

Answer 833

In the wall of the alimentary canal and controls peristalsis

Its activity is unregulated by the parasympathetic nervous system and down regulated by the sympathetic nervous system

Question 834

Hormones that regulate feeding behavior

Answer 834

Antidiuretic hormone (ADH or vasopressin), aldosterone, glucagon, ghrelin, leptin and cholecystokinin

Question 835

How does antidiuretic hormone (ADH or vasopressin) regulate feeding behavior?

Answer 835

Promotes thirst

Question 836

How does aldosterone regulate feeding behavior?

Answer 836

Promotes thirst

Question 837

How does glucagon regulate feeding behavior?

Answer 837

Promotes hunger

Question 838

How does ghrelin regulate feeding behavior?

Answer 838

Promotes hunger

Question 839

How does leptin regulate feeding behavior?

Answer 839

Promotes satiety

Question 840

How does cholecystokinin regulate feeding behavior?

Answer 840

Promotes satiety

Question 841

Digestion in the oral cavity

Answer 841

Mastication starts the mechanical digestion of food
Salivary amylase and lipase start the chemical digestion food
Food is formed into a bolus and swallowed

Question 842

Pharynx

Answer 842

Connects the moth and posterior nasal cavity to the esophagus

Question 843

Esophagus

Answer 843

Propels food to the stomach using peristalsis

Question 844

How does food enter the stomach?

Answer 844

Through the lower esophageal (cardiac) sphincter)

Question 845

Parts of the stomach

Answer 845

Fundus, body, antrum and pulorus

Question 846

Stomach

Answer 846

Has a lesser and greater curvature and is thrown into folds called rugae

Question 847

Secretory cells lining the stomach

Answer 847

Mucous cells, chief cells, partial cells and G-cells

Question 848

Pepsinogen

Answer 848

Secreted by chief cells in the stomach

A protease activated by the acidic environment of the stomach

Question 849

Gastrin

Answer 849

Secreted by G-cells in the stomach

A peptide hormone that increases HCl secretion and gastric motility

Question 850

Chyme

Answer 850

Food particles that have undergone mechanical and chemical digestion in the stomach

Question 851

How does food pass into the duodenum?

Answer 851

Through the pyloric sphincter

Question 852

Duodenum

Answer 852

The first part of the small instance

Primarily involved in chemical digestion

Question 853

Disaccharidases

Answer 853

Brush-border enzymes that break down maltose, iso-maltose, lactose, and sucrase into monosaccharides

Question 854

Peptidases

Answer 854

Brush-border enzymes

Question 855

Types of peptidases

Answer 855

Aminopeptidase and dipeptidase

Question 856

Acinar cells

Answer 856

In the pancreas

Produce pancreatic juices that contain bicarbonate, pancreatic amylase, pancreatic peptidases and pancreatic lipase

Question 857

Pancreatic peptidases

Answer 857

Trypsinogen, chymotrypsinogen, carboxypeptidases A and B

Question 858

Bile

Answer 858

Emulsifies fats, making them soluble and creasing their surface area

Question 859

Gallbladder

Answer 859

Stores and concentrates bile

Question 860

Jejunum

Answer 860

In the small intestine

Primarily involved in absorption

Question 861

Ileum

Answer 861

In the small intestine

Primarily involved in absorption

Question 862

What is the small intestine lined with?

Answer 862

Villi

Question 863

What are the villi of the small intestine covered with?

Answer 863

Microvilli

Question 864

Microvilli

Answer 864

Cover the villi of the small intestine to increase their surface are available for absorption

Question 865

Lacteal

Answer 865

A vessel of the lymphatic system

Question 866

Large intestine

Answer 866

Absorbs water and salts, forming semisolid feces

Question 867

Cecum

Answer 867

An out pocketing that accepts fluid from the small intestine through the iléocaecal valve
The site of attachment of the appendix

Question 868

Colon divisions

Answer 868

Ascending, transverse, descending and sigmoid portions

Question 869

Rectum

Answer 869

Stores feces

Question 870

Anus

Answer 870

Excretes feces

Question 871

What do gut bacteria produce?

Answer 871

Vitamin K and biotin (vitamin B7)

Question 872

Biotin

Answer 872

Vitamin B7

Question 873

Do G-cells produce HCl?

Answer 873

No, they produce gastrin

Question 874

What produces HCl in the stomach?

Answer 874

Parietal cells

Question 875

Do chief cells produce pepsinogen?

Answer 875

Yes

Question 876

Do parietal cells produce alkaline mucus?

Answer 876

No, they they produce HCl and intrinsic factors

Question 877

What produces alkaline mucus in the stomach?

Answer 877

Mucous cells

Question 878

Do mucous cells produce intrinsic factor?

Answer 878

No, they produce alkaline mucus

Question 879

What produces intrinsic factor in the stomach?

Answer 879

Parietal cells

Question 880

In an experiment, enteropeptidase secretion was blocked. As a direct realist, levels of all of the following active enzymes would likely be affected except:

a. Trypsin
b. Aminopeptidase
c. Chymotrypsin
d. Carboxypeptidase A

Answer 880

Aminopeptidase

Aminopeptidase is a brush-border peptidase secreted by the cells lining the duodenum; it does not require enteropeptidase for activation. Both trypsinogen and procarboxypeptidases A and B are activated by enteropeptidase. Once activated, trypsin can activate chymotrupsinogen; if trypsinogen cannot be activated, then chymotrypsinogen will not be activated either.

Question 881

Does trypsin hydrolyze specific peptide bonds?

Answer 881

Yes

Question 882

Does lactase hydrolyze lactose to glucose and galactose?

Answer 882

Yes

Question 883

Does pancreatic amylase hydrolyze starch to maltose?

Answer 883

Yes

Question 884

Does lipase emulsify fats?

Answer 884

No, it is involved in the digestion of fats chemically in the duodenum, allowing them to be brought into duodenal cells and packaged into chylomicrons

Question 885

What emulsifies fats in the intestines?

Answer 885

Bile

Question 886

Where are proteins digested?

Answer 886

In the stomach and small intestines

Question 887

Stomach digestion of proteins

Answer 887

Pepsin (secreted as pepsinogen) hydrolyzes specific peptide bonds

Question 888

Small intestines digestion of proteins

Answer 888

Trypsin (secreted as trypsinogen), chymotrypsin (secreted as chymotrypsinogen), carboxypepdases A and B (secreted as procarboxypeptidases A and B), amino peptidase and dipeptidases hydrolyze specific parts of the peptide

Question 889

Is sucrase secreted by the salivary glands?

Answer 889

No, it is a brush-border enzyme found on duodenal cells

Question 890

Is carboxypeptidase secreted by the pancreas?

Answer 890

Yes

Question 891

Is trypsin secreted by the pancreas?

Answer 891

Yes

Question 892

Is lactase secreted by the duodenum?

Answer 892

Yes

Question 893

A two-week-old male infant is bright to the ER. His mother reports that he has been unable to keep any milk down; shortly after he nurses, he has sudden projectile vomiting. During exam, an olive-shaped mass can be felt in his upper abdomen. It is determined that there is a constriction in the digestive system that prevents food from reaching the small instant from the stomach. Which structure is most likely the site of the problem?

Answer 893

Pyloric sphincter

Question 894

Many medications have anticholinergic side effects, which block the activity of parasympathetic neurons throughout the body. Older individuals may be on many such medications simultaneously, exacerbating the side effects. Which of the following would not be expected in an individual taking medications with anticholinergic activity?

a. Dry mouth
b. Diarrhea
c. Slow gastric emptying
d. Decreased gastric acid production

Answer 894

Diarrhea

Question 895

Enzymes in the stomach function in which pH range?

Answer 895

Acidic pH

Question 896

Enzymes in the duodenum function in which pH range?

Answer 896

Neutral-slightly alkaline pH

Question 897

Cholangiocarcinoma: a cancer of the bile ducts that can ultimately lead to full occlusion of the duct lumen

Can it lead to elevated levels of bilirubin in the blood?

Answer 897

Yes

Question 898

Autoimmune hemolytic anemia: a disease in which the RBCs are attacked by antibodies and are lysed

Can it lead to elevated levels of bilirubin in the blood?

Answer 898

Yes

Question 899

Ménétrier’s disease: rugae thicken and overlying glands lose secretory ability

Can it lead to elevated levels of bilirubin in the blood?

Answer 899

No

Question 900

Acetaminophen (Tylenol) overdose: the accumulation go toxic metabolites can cause rapid liver failure

Can it lead to elevated levels of bilirubin in the blood?

Answer 900

Yes

Question 901

Elevated bilirubin

Answer 901

Implies a blockage to bile flow, increased production of bilirubin (from massive hemoglobin release), or an inability of the liver to produce bile

Question 902

Rugae

Answer 902

Folds in the stomach wall

Question 903

What is the primary site of chylomicrons absorption?

Answer 903

Lacteals in small intestines

Question 904

What is the primary site of amino acid absorption?

Answer 904

Capillary beds in small intestines

Question 905

What is the primary site of vitamins A and E absorption?

Answer 905

Lacteals in small intestines

Question 906

What is the primary site of cholesterol absorption?

Answer 906

Lacteals in small intestines

Question 907

Starch is hydrolyzed into maltose by enzymes from:

Answer 907

Salivary glands and pancreas

Question 908

Does vitamin D (cholecalciferol) drain to the liver before arriving at the right side of the heart?

Answer 908

No

Question 909

Does threonine (an amino acid) drain to the liver before arriving at the right side of the heart?

Answer 909

Yes

Question 910

Does fructose (a monosaccharide) drain to the liver before arriving at the right side of the heart?

Answer 910

Yes

Question 911

Does vitamin B5 (pantothenic acid) drain to the liver before arriving at the right side of the heart?

Answer 911

Yes

Question 912

Where do capillary beds in the small intestines lead to?

Answer 912

They come together, forming the portal vein, which drains to the liver

Question 913

Where do lacteals in the small intestines lead to?

Answer 913

They come together, forming the thoracic duct, which drains directly into the left subclavian vein

Question 914

Structures in the excretory pathway

Answer 914

Bowman’s space –> proximal convoluted tubule –> descending limb of the loop of Henle –> ascending limb of the loop of Henle –> distal convoluted tubule –> collecting duct –> renal pelvis –> ureter –> bladder –> urethra

Question 915

Vessels in the renal vascular pathway

Answer 915

Renal artery –> afferent arteriole –> glomerulus –> efferent arteriole –> vasa recta –> renal vein

Question 916

What arm of the nervous system is responsible for contraction of the detrusor muscle?

Answer 916

The parasympathetic system

Question 917

What are the three processes by which solutes are exchanged between the filtrate and the blood?

Answer 917

Filtration, secretion and reabsorption

Question 918

Bowman’s capsule

Answer 918

The site of filtration, through which water, ions, amino acids, vitamins, and glucose pass (essentially everything besides cells and proteins)

Question 919

Proximal convoluted tubule (PCT)

Answer 919

Controls solute identity, reabsorbing vitamins, salt, water, amino acids and glucose, while secreting potassium and hydrogen ions, ammonia and urea

Question 920

Descending limb of the loop of Henle

Answer 920

Water reabsorption using the medullary concentration gradient
Permeable to water, but not salt

Question 921

Ascending limb of the loop of Henle

Answer 921

Salt reabsorption and allowing dilution go the urine in the diluting segment (passive and active reabsorption)
Permeable to salt, but not water

Question 922

Distal convoluted tubule (DCT)

Answer 922

Reabsorbing salts while secreting potassium and hydrogen ions, ammonia and urea
Responsive to aldosterone only

Question 923

Collecting duct

Answer 923

Urine concentration
Its variable permeability allows water to be reabsorbed based on the needs of the body
Responsive to aldosterone and antidiuretic hormone

Question 924

Filtration

Answer 924

The movement of solutes from blood into filtrate at Bowman’s capsule
The direction and rate of filtration is determined by Starling forces, which account for the hydrostatic and oncotic pressure differentials between the glomerulus and Bowman’s space

Question 925

Secretion

Answer 925

The movement of solutes from blood into filtrate anywhere besides Bowman’s capsule

Question 926

Reabsorption

Answer 926

The movement of solutes from filtrate into blood

Question 927

What is the predominant cell type in the epidermis?

Answer 927

Keratinocytes

Question 928

What are the layers of the epidermis, from superficial to deep?

Answer 928

Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale

Question 929

What are the layers of the dermis, from superficial to deep?

Answer 929

Papillary layer

Reticular layer

Question 930

What are some mechanisms the body uses to cool itself?

Answer 930

Sweating

Vasodilation

Question 931

What are some mechanisms the body uses to retain heat?

Answer 931

Shivering
Vasoconstriction
Piloerection
Insulation provided by fat

Question 932

Excretory system

Answer 932

Regulation of blood pressure
Blood osmolarity
Acid-base balance
Removal of nitrogenous wastes

Question 933

Kidney

Answer 933

Produces urine

Question 934

Pathway of urine

Answer 934

Leaves the kidney –> renal pelvis –> ureter –> bladder –> urethra

Question 935

Parts go the kidney

Answer 935

Cortex, medulla, hilum

Question 936

Kidney hilum

Answer 936

Contains a renal artery, renal vein and ureter

Question 937

Does the kidney contain a portal system (two capillary beds in series)?

Answer 937

Yes

Question 938

Blood flow in the renal portal system

Answer 938

Renal artery –> afferent arterioles –> glomeruli in Bowman’s capsule (the first capillary bed) –< efferent arteriole –> vasa recta –> nephron (second capillary bed) –> renal vein

Question 939

Detrusor muscle

Answer 939

The bladder muscular lining

Is under parasympathetic control

Question 940

Bladder sphincters

Answer 940

Internal urethral sphincter and external urethral sphincter

Question 941

Internal urethral sphincter

Answer 941

Consists of smooth muscle and is under involuntary (parasympathetic) control

Question 942

External urethral sphincter

Answer 942

Consists of skeletal muscle and is under voluntary control

Question 943

Countercurrent multiplier system

Answer 943

Created by the flows in the vasa recta and nephron being in opposite directions
Allows for maximal reabsorption of water

Question 944

Where is the diluting segment in the ascending limb of the loop of Henle?

Answer 944

In the outer medulla, because salt is actively reabsorbed in this site. The solution is, therefore, hypotonic compared to the blood.

Question 945

How does the kidney function when blood pressure (and volume) are low?

Answer 945

Aldosterone (steroid hormone regulated by the renin-angiotensin-aldosterone system) increases sodium reabsorption in the distal convoluted tubule and collecting duct, there by increasing water reabsorption. This results in an increased blood volume (and pressure), but no change in blood osmolarity.

Antidiuretic hormone (ADH or vasopressin :: a peptide hormone synthesized by the hypothalamus and released by the posterior pituitary :: stimulated by low blood volume and high blood osmolarity) increases the permeability of the collecting duct to water, increasing water reabsorption. This results in an increased blood volume (and pressure) and a decreased blood osmolarity.

Question 946

How can the kidney regulate pH?

Answer 946

By selective reabsorption or secretion of bicarbonate or hydrogen ions

Question 947

Skin

Answer 947

Acts as a barrier, protecting from the elements and invasion by pathogens
Thermoregulation (maintenance of a constant internal temperature)
Prevention of dehydration and salt loss from the body

Question 948

Skin layers

Answer 948

Hypodermis (subcutaneous layer), dermis and epidermis

Question 949

Stratum basale

Answer 949

Contains temp cells that proliferate to form keratinocytes

Question 950

Keratinocytes

Answer 950

Their nuclei are lost in the status granulosum and many thin layers form in the stratum corneum

Question 951

Melanocytes

Answer 951

Produce melanin

Question 952

Melanin

Answer 952

Protects the skin from DNA damage caused by ultraviolet radiation
Passed to the keratinocytes

Question 953

Langerhans cells

Answer 953

Special macrophages that serve as antigen-presenting cells in the skin

Question 954

Where are the sensory cells in the skin located?

Answer 954

In the dermis

Question 955

Sensory cells in the dermis

Answer 955

Merkel cells (deep pressure and texture), free nerve endings (pain), Meissner’s corpuscles (light touch), Ruffini endings (stretch) and Pacinian corpuscles (deep pressure and vibration)

Question 956

Merkel cells detect:

Answer 956

Deep pressure and texture

Question 957

Meissner’s corpuscles detect:

Answer 957

Light tough

Question 958

Free nerve endings in the dermis detect:

Answer 958

Pain

Question 959

Ruffini endings detect:

Answer 959

Stretch

Question 960

Pacinian corpuscles detect:

Answer 960

Deep pressure and vibration

Question 961

What are sweat glands intreated by?

Answer 961

Postganglionic cholinergic sympathetic neurons

Question 962

Piloerection

Answer 962

Arrector pili muscles contract, causing hairs to stand on end, trapping a layer of warmed air around the skin

Question 963

Where in the nephron is sodium actively transported?

Answer 963

Proximal convoluted tubule, distal convoluted tubule and the thick ascending loop of Henle

Question 964

Which region of the kidney has the lowest solute concentration under normal physiological circumstances?

Answer 964

The cortex

Question 965

In the nephron, amino acids enter the casa recta via the process of:

Answer 965

Reabsorption

Question 966

On a very cold day, a man waits for over an hour at the bus stop. Which structure helps his body set and maintain a normal temperature?

Answer 966

The hypothalamus

Question 967

Glucose reabsorption in the nephron occurs in the:

Answer 967

Proximal convoluted tubule

Question 968

Under normal physiological circumstances, the primary function of the nephron is to create urine that is hypertonic, hypotonic or isotonic to the blood?

Answer 968

Hypertonic

Question 969

Diabetic nephropathy is commonly detected by finding protein in the urine of a patient. In such a disease, where is the likely defect in the nephron?

Answer 969

The glomerulus

Question 970

A laceration cuts down into a layer of loose connective tissue in the skin. Which layer of the skin is this?

Answer 970

Papillary layer

Question 971

Papillary layer

Answer 971

In the dermis

Predominantly loose connective tissue

Question 972

Stratum corneum

Answer 972

In the epidermis

Contains dead keratinocytes

Question 973

Stratum lucidum

Answer 973

In the epidermis

Contains dead keratinocytes

Question 974

Reticular layer

Answer 974

In the dermis

Predominantly dense connective tissue

Question 975

When the pH of the blood is high, which substance is likely to be excreted in larger quantities in the urine?

Answer 975

Bicarbonate ions

Question 976

In which layer of the skin can the stem cells of keratinocytes be found?

Answer 976

Stratum basale

Question 977

Sarin is a potent organophosphate that can be used in chemical warfare. As an inhibitor of acetylcholinesterase, sarin causes excessive buildup of acetylcholine in all synapses where it is the neurotransmitter.

Is urination likely to increase or decrease?
Is sweating likely to increase or decrease?

Answer 977

Urination is likely to increase and sweating is likely to increase

An excess of acetylcholine will lead to activation of all parasympathetic neurons, pre-ganglionic sympathetic neurons, and the post-ganglionic sympathetic neurons that interval sweat gland. Because the parasympathetic nervous system causes contractions of the bladder, one would expect increased urination. The increased activation of swat glands would lead to increased sweating as well.

Question 978

Which type(s) of muscles is(are) striated?

Answer 978

Skeletal and cardiac

Question 979

Which type(s) of muscles is(are) always uninucleated?

Answer 979

Smooth

Question 980

Which type(s) of muscles is(are) always polynucleated?

Answer 980

Skeletal

Question 981

Which type(s) of muscles is(are) voluntary?

Answer 981

Skeletal

Question 982

Which type(s) of muscles is(are) innervated by the autonomic nervous system?

Answer 982

Smooth and cardiac

Question 983

Which type(s) of muscles is(are) exhibiting myogenic activity?

Answer 983

Smooth and cardiac

Question 984

Which zone or band in the sarcomere does not change its length during muscle contraction?

Answer 984

A-band :: it is the enter length of the myosin filament. Filaments do not change length, but rather slide over each other.

Question 985

What are the events that initiate muscle contraction?

Answer 985

Release of acetylcholine from motor neuron –> activation of acetylcholine receptors in sarcolemma –> depolarization of sarcolemma –> spreading of signal using T-tubules –> release of calcium from sarcoplasmic reticulum (SR) –> binding of calcium to troponin –> conformational shift of tropomyosin –> exposure of myosin-binding sites –> myosin binds to actin

Question 986

What role does the binding of ATP to the myosin head play in the cross bridge cycle?

Answer 986

It allows the myosin filament to disconnect from actin

Question 987

What role does the dissociated of ADP and inorganic phosphate from the myosin head play in the cross bridge cycle?

Answer 987

It causes the powerstroke

Question 988

Tetanus (the physiological phenomenon, not the disease)

Answer 988

The summation of multiple simple twitches that occur too quickly for the muscle to relax, leading to a stronger and more prolonged contraction of the muscle

Question 989

Compact bone

Answer 989

Dense
Used for strength
Forms most of the outer layers of a bone

Question 990

Spongy (cancellous) bone

Answer 990

Has many spaces between bony spicules called trabeculae
The sire of marrow production
Found in the interior core of the bone
Helps distribute forces or pressures on the bone

Question 991

Structural parts of a bone

Answer 991

Diaphysis –> metaphyses –> epiphyses (which have epiphyseal [growth] plates)

Question 992

Which part of the bone contributes most to linear growth?

Answer 992

Epiphyses :: it has the growth plates that contribute to linear growth

Question 993

What chemical forms most of the inorganic component of bone?

Answer 993

Hydroxyapatite crystals

Question 994

Osteoblast

Answer 994

Build bone

Question 995

Osteoclast

Answer 995

Chew bone (break it down)

Question 996

Chondrocyte

Answer 996

Form cartilage

Question 997

What liquid provides the lubrication for movable joints?

Answer 997

Synovial fluid

Question 998

What tissue produces synovial fluid

Answer 998

Synovium

Question 999

Synovial fluid

Answer 999

Lubricates movable joints

Question 1000

Types of muscles

Answer 1000

Skeletal, smooth and cardiac

Question 1001

Skeletal muscles

Answer 1001

Involved in support and movement
involved in propulsion of blood in the venous system
Involved in thermoregulation
Appear striated
Are under voluntary (somatic) control
Are polynucleated
Can be divided into red (slow-twitch) fibers and white (fast-twitch) fibers

Question 1002

Red (slow-twitch) fibers

Answer 1002

Carry out oxidative phosphorylation

Question 1003

White (fast-twitch) fibers)

Answer 1003

Rely on anaerobic metabolism

Question 1004

Smooth muscles

Answer 1004

In the respiratory, reproductive, cardiovascular and digestive systems
Appear non-striated
Are under involuntary (autonomic) control
Are uninucleated
Can display myogenic activity

Question 1005

Myogenic activity

Answer 1005

Contraction without neural input

Question 1006

Cardiac muscles

Answer 1006

Comprise the contractile tissue of the heart
Appear striated
Are under involuntary (autonomic) control
Are uninucleated (sometimes binucleated)
Can display myogenic activity
Cells are connected with intercalated disks that contain gap junctions

Question 1007

Sarcomere

Answer 1007

The basic contracile unit of striated muscle

Question 1008

What are sarcomeres made of?

Answer 1008

Thick (myosin) and thin (actin) filaments

Question 1009

Where is troponin found on the sarcomere?

Answer 1009

Thin (actin) filament

Question 1010

Where is tropomyosin found on the sarcomere?

Answer 1010

Thin (actin) filamentThin (actin) filament

Question 1011

What does troponin do?

Answer 1011

Regulates the actin-myosin interactions

Question 1012

What does tropomyosin do?

Answer 1012

Regulates the actin-myosin interactions

Question 1013

Divisions of the sarcomere

Answer 1013

Z-lines, M-line, I-band, H-zone, and A-band

Question 1014

Z-lines

Answer 1014

The boundaries of the sarcomere

Question 1015

M-line

Answer 1015

Located in the middle of the sarcomere

Question 1016

I-band

Answer 1016

Contains only thin filaments

Question 1017

H-zone

Answer 1017

Contains on thick filaments

Question 1018

A-band

Answer 1018

Contains all the thick filaments

The only part of the sarcomere that maintains a constant size during contraction

Question 1019

Myofibrils

Answer 1019

Sarcomeres attached end-to-end

Question 1020

Myocyte (muscle cell or muscle fiber)

Answer 1020

Contains many myofibrils

Question 1021

Sarcoplasmic reticulum

Answer 1021

Surrounds myofibrils

A calcium-containing modified ER

Question 1022

Sarcolemma

Answer 1022

The cell membrane of a myocyte

Question 1023

T-tubules

Answer 1023

Connected to the sarcolemma and oriented perpendicularly to myofibrils, allowing the incoming signal to reach all parts of the muscle

Question 1024

Where does muscle contraction begin?

Answer 1024

At the neuromuscular junction

Question 1025

Neuromuscular junction

Answer 1025

Where the motor neuron releases acetylcholine, which binds to receptors on the sarcolemma, causing depolarization

Question 1026

What happens when the sarcolemma is depolarized?

Answer 1026

The depolarization spreads down the sarcolemma to the T-tubules, triggering the release of calcium ions

Question 1027

What happens when calcium ions are released?

Answer 1027

Calcium bins to troponin, causing a shift in tropomyosin and exposure of the myosin-binding sites on the actin thin filament

Question 1028

When does the shortening of the sarcomere occur?

Answer 1028

When myosin heads bind to the exposed sites on actin, forming cross bridges and pulling the actin filament alone the thick filament, resulting in contraction :: the sliding filament model

Question 1029

When does the muscle relax?

Answer 1029

When acetylcholine is degraded by acetylcholinesterase, terminating the signal and allowing calcium to be Brough back into the SR. ATP binds to the myosin head, allowing it to release from actin

Question 1030

Simple twitch

Answer 1030

Muscle cells exhibiting an all-or-nothing response

Question 1031

Frequency summation

Answer 1031

Addition of multiple simple twitches before the muscle has an opportunity to fully relax

Question 1032

How do muscle cells reduce oxygen debt?

Answer 1032

Muscle cells have additional energy reserves

Question 1033

Why is it important for muscles cells to reduce oxygen debt?

Answer 1033

To forestall fatigue

Question 1034

Oxygen debt

Answer 1034

The difference between the amount of oxygen needed and the amount of oxygen present

Question 1035

Creatine phosphate

Answer 1035

Transfer a phosphate group to ADP, forming ATP

Question 1036

Myoglobin

Answer 1036

Heme-containing protein that is a muscular oxygen reserve

Question 1037

Endoskeleton

Answer 1037

Internal skeleton

Question 1038

Exoskeleton

Answer 1038

External skeleton

Question 1039

Divisions of human skeletal system

Answer 1039

Axial and appendicular skeletons

Question 1040

Axial skeleton

Answer 1040

Consists of structures in the midline

e.g. skull, vertebral column, ribcage and hyoid bone

Question 1041

Appendicular skeleton

Answer 1041

Consists of the bones of the limbs and the pectoral grille and the pelvis

Question 1042

Which embryonic layer gives rise to bones?

Answer 1042

Mesoderm

Question 1043

Types of bones

Answer 1043

Compact and spongy (cancellous)

Question 1044

Periosteum

Answer 1044

A layer of connective tissue that surrounds bone
Serves as a site of attachment of bone to muscle
Cells of the periosteum may differentiate into osteoblasts

Question 1045

How are bones attached to muscles?

Answer 1045

Tendons

Question 1046

How are bones attached to each other?

Answer 1046

Ligaments

Question 1047

Bone matrix

Answer 1047

Has organic components, like collagen, glycoproteins and other peptides
Has inorganic components, like hydroxyapatite

Question 1048

Bone organization

Answer 1048

Bones are organized into concentric rings called lamellae around a central Harversian or Volkmann’s canal. This structural unit is called an osteon, or Haversian system
Between lamellar rings are lacunae, where osteocytes reside, which are connected with canaliculi to allow for n’eurent and waste transfer

Question 1049

What is the role of parathyroid hormone in bone building/breakdown?

Answer 1049

It increases resorption of bone, increasing calcium and phosphate concentrations in the blood

Question 1050

What is the role of vitamin D in bone building/breakdown?

Answer 1050

Increases resorption of bone, leading to increased turnover and, subsequently, the production of stronger bones

Question 1051

What is the role of calcitonin in bone building/breakdown?

Answer 1051

Increases bone formation, decreasing calcium concentration in the blood

Question 1052

Cartilage

Answer 1052

A firm, elastic material secreted by chondrocytes
Found in areas that require more flexibility or cushioning
Avascular
Not innervated

Question 1053

Chondrocytes

Answer 1053

Secrete cartilage

Question 1054

Chondrin

Answer 1054

Cartilage matrix

Question 1055

How do bones form in fetal life?

Answer 1055

From cartilage through endochondral ossification

Question 1056

Where do the bones in the skull form from?

Answer 1056

Undifferentiated tissue (mesenchyme) in intramembranous ossification

Question 1057

Joint classifications

Answer 1057

Immovable or movable

Question 1058

Immovable joints

Answer 1058

Fused together to form sutures or similar fibrous joints

Question 1059

Movable joints

Answer 1059

Strengthened by ligaments and contain a synovial capsule

Question 1060

Articular cartilage

Answer 1060

Coats each bone in the joint

Aids in movement and provides cushioning

Question 1061

Antagonistic pairs

Answer 1061

Muscles that serve opposite functions :: when one muscle contracts, the other lengthens

Question 1062

An X-ray of the right femur in a child shows that it is shorter than the opposite femur, and below the average length for a child of this age. Which region of the bone is most likely to have caused this abnormality?

Answer 1062

Epiphysis

Question 1063

When the knee moves back and forth during walking, what prevents the surfaces of the leg bones from rubbing against each other?

Answer 1063

Articular cartilage

Question 1064

Yellow bone marrow

Answer 1064

Contains predominantly adipose tissue

Question 1065

To facilitate the process of birth, an infant’s head is somewhat flexible. This flexibility is given in part by the two fontanelles, which are soft spots of connective tissue in the infant’s skull. With time, the fontanelles will close through a process known as:

Answer 1065

Intramembranous ossification

Question 1066

A young woman presents to the ER with a broken hip. She denies any recent history of trauma to the joint. Blood tests reveal a calcium concentration of 11.5 mg/dL (normal: 8.4 – 10.2). Which tissue is likely responsible for these findings?

Answer 1066

Parathyroid

Question 1067

What does it mean for an allele to be dominant?

Answer 1067

Requires only one copy for expression

Question 1068

What does it mean for an allele to be recessive?

Answer 1068

Requires two copies for expression

Question 1069

What does it mean for a genotype to be homozygous?

Answer 1069

Both alleles are recessive or both alleles are dominant

Question 1070

What does it mean for a genotype to be heterozygous?

Answer 1070

One allele is recessive and the other is dominant

Question 1071

What does it mean for a genotype to be hemizygous?

Answer 1071

There is only one allele for a given gene

Question 1072

Complete dominance

Answer 1072

Occurs when a gene has only one dominant and one recessive allele

Question 1073

Codominance

Answer 1073

Occurs when a gene has more than one dominant allele and two different dominant allele can be expressed simultaneously

Question 1074

Incomplete dominance

Answer 1074

Occurs when a gene has no dominant allele and heterozygotes have phenotypes that are intermediate between homozygotes

Question 1075

Penetrance

Answer 1075

The portion of the population that expresses a phenotype, given a particular genotype

Question 1076

Expressivity

Answer 1076

The differences in expression (severity, location, etc.) of a phenotype across affected members of a population

Question 1077

Which phase of meiosis most closely correlates to Mendel’s first law?

Answer 1077

Anaphase I

Question 1078

Which phase of meiosis most closely correlates to Mendel’s second law?

Answer 1078

Prophase I

Question 1079

Types of point mutations

Answer 1079

Silent
Missense
Nonsense

Question 1080

Silent mutation

Answer 1080

Change in the nucleotide at the wobble position

No change in the amino acid produced

Question 1081

Missense mutation

Answer 1081

Change one nucleotide to another that results in change from one amino acid to another

Question 1082

Nonsense mutation

Answer 1082

Change one nucleotide to another that results in change from one amino acid to a stop codon
Shortened protein

Question 1083

Types of frameshift mutation

Answer 1083

Insertion

Deletion

Question 1084

Types of chromosomal mutations

Answer 1084

Deletion
Duplication
Inversion
Insertion
Translocation

Question 1085

Duplication mutation

Answer 1085

Occur when a segment of DNA is copied multiple times in the genome

Question 1086

Inversion mutation

Answer 1086

Occur when a segment of DNA is reversed in the genome

Question 1087

Translocation mutation

Answer 1087

Occur when a segment of DNA is from one chromosome is swapped with a segment of DNA from another chromosome

Question 1088

Why would genetic leakage in animals be rare prior to the last century?

Answer 1088

It requires the formation of a hybrid organism that can then mate with members of one or the other parent species. While hybrids existed historically (especially mules), fertile hybrids were certainly rare before a more modern understanding of genetics (and a commercial, financial or academic impetus to create these organisms).

Question 1089

Why is genetic drift more common in small populations?

Answer 1089

It occurs due to chance, so its effects will be more pronounced with a smaller sample size.

Question 1090

The founder effect

Answer 1090

Occurs when a small group is reproductively isolated from the larger population, allowing certain alleles to take on a higher prevalence in the group than the rest of the population

Question 1091

All five criteria of the Hardy-Weinberg principle are required to imply what characteristic of the study population?

Answer 1091

The study population is not undergoing evolution; thus, the allele frequencies will remain stable over time

Question 1092

Natural selection

Answer 1092

Certain traits that arise from chance are more favorable for reproductive success in a given environment, and that that those traits will be passed on to future generations

Question 1093

Modern synthesis model (Neo-Darwinism)

Answer 1093

Selection is for specific alleles, which are passed to future generations through formation of gametes, and that these favorable traits arise from mutations

Question 1094

Inclusive fitness

Answer 1094

Reproductive success of an organism is not only due to the number of offspring it creates, but also the ability to care for young (that can then care for other); it explains changes not only at the individual level, but based on the survival of the species (and that individual’s alleles within the species, including in other related individuals).

Question 1095

Punctuated equilibrium

Answer 1095

For some species, little evolution occurs for a long period, which is interrupted by rapid bursts of evolutionary change

Question 1096

Patterns of selection

Answer 1096

Stabilizing
Directional
Disruptive

Question 1097

Change in population phenotype does the stabilizing pattern of selection bring?

Answer 1097

Loss of extremes, maintenance of phenotype in a small window

Question 1098

Change in population phenotype does the directional pattern of selection bring?

Answer 1098

Movement towards one extreme or the other

Question 1099

Change in population phenotype does the disruptive pattern of selection bring?

Answer 1099

Movement towards both extremes with loss of the norm

Speciation may occur

Question 1100

Patterns of evolution

Answer 1100

Divergent
Parallel
Convergent

Question 1101

What is the outcome of a divergent pattern of evolution?

Answer 1101

Two species with a common ancestor become less similar because of different evolutionary pressures

Question 1102

What is the outcome of a parallel pattern of evolution?

Answer 1102

Two species with a common ancestor remain similar because of similar evolutionary pressures

Question 1103

What is the outcome of a convergent pattern of evolution?

Answer 1103

Two species with no recent common ancestor become more similar because of similar evolutionary pressures

Question 1104

Species

Answer 1104

The largest group of organisms capable of breeding to form fertile offspring
Reproductively isolated from each other by pre- or post-zygotic mechanisms

Question 1105

Hardy-Weinberg equations

Answer 1105

p + q = 1

p^2 + 2pq + q^2 = 1

Question 1106

Alleles

Answer 1106

Alternative forms of a gene

Question 1107

Genotype

Answer 1107

The combination of alleles one has at a given genetic locus

Question 1108

Phenotype

Answer 1108

The observable manifestation of a genotype

Question 1109

Mendel’s first law of segregation

Answer 1109

States that an organism has two alleles for each gene, which segregate during meiosis, resulting in gametes carrying only one allele for a trait

Question 1110

Mendel’s second law of independent assortment

Answer 1110

The inheritance of one allele does not influence the probability of inheriting a given allele for a different trait

Question 1111

Griffith experiment

Answer 1111

Demonstrated the transforming principle, converting non-virulent bacteria into virulent bacteria by exposure to heat-killed virulent bacteria

Question 1112

Avery-MacLeod-McCarty experiment

Answer 1112

Demonstrated that DNA is the genetic material because degradation of DNA led to a cessation of bacterial transformation

Question 1113

Hershey-Chase experiment

Answer 1113

Confirmed that DNA is the genetic material because only radio labeled DNA could be found in bacteriophage-infected bacteria

Question 1114

Gene pool

Answer 1114

Composed of all the alleles in a given population

Question 1115

Mutations

Answer 1115

Changes in DNA sequence

Question 1116

Deletion mutation

Answer 1116

Occurs when a large segment of DNA is lost

Question 1117

Insertion mutation

Answer 1117

Occurs when a segment of DNA is moved from one chromosome to another

Question 1118

Bottleneck effect

Answer 1118

Suddenly isolates a small population

Question 1119

Outcomes of the bottleneck effect

Answer 1119

Founder effect and inbreeding

Question 1120

Punnet squares

Answer 1120

Visually represent the crossing of gametes from parents to show relative genotypic and phenotypic frequencies

Question 1121

Monohybrid cross

Answer 1121

Accounts for one gene

Question 1122

Dihybrid cross

Answer 1122

Accounts for two genes

Question 1123

Sex-linked cross

Answer 1123

Sex chromosomes are usually used to indicate sec as well as genotype

Question 1124

Recombination frequency

Answer 1124

The likelihood of two alleles being separated during crossing over in meiosis

Question 1125

Genetic maps

Answer 1125

Can be made using recombination frequency as the scale in centimorgans

Question 1126

Hardy-Weinberg principle

Answer 1126

States that if a population meets certain criteria (aimed at a lack of evolution), then the allele frequencies will remain constant (Hardy-Weinberg equilibrium)

Question 1127

Adaptive radiation

Answer 1127

The rapid emergence of multiple species from a common ancestor, each of which occupies its own ecological niche

Question 1128

Molecular clock model

Answer 1128

The degree of difference in the genome between two species is related to the amount of time since the two species broke off from a common ancestor

Question 1129

If a test cross on a species reveals the appearance of a recessive phenotype in the offspring, what must be true of the phenotypically dominant parent?

Answer 1129

It must be genotypically heterozygous

Question 1130

In a species of plant, a homozygous red flower (RR) is crossed with a homozygous yellow flower (rr). If the G1 generation is self-crossed and the F2 generation has a phenotypic ratio of red:orange:yellow of 1:2:1, which characteristic accounts for these results?

Answer 1130

Incomplete dominance

Question 1131

The five criteria of the Hardy-Weinberg principle

Answer 1131

1. The population is very large
2. There are no mutations that affect the gene pool
3. Mating between individuals in the population is random
4. There is no migration of individuals into or out of the population
5. The genes in the population are all equally successful at reproduction

Question 1132

As the climate became colder during the Ice Age, a particular species of mammal evolved a thicker layer of fur. What kind of selection occurred in this population?

Answer 1132

Directional selection

Question 1133

At what point are two populations descended from the same ancestral stock considered to be separate species?

Answer 1133

When they can no longer produce viable, fertile offspring

Question 1134

Darwin’s main argument in his theory of evolution

Answer 1134

Natural selection is the driving force for evolution
There is a struggle for survival among organisms
Those individuals with fitter variations will survive and reproduce

Question 1135

Did Darwin consider the role of genetic mutation and recombination?

Answer 1135

No because they were unknown at the time

Question 1136

A child is born with a number of unusual phenotypic features and genetic testing is performed. The child is determined to have partial trisomy 21, with three copies of some segments of DNA from chromosome 21, and partial monosomy 4, with only one copy of some segments of DNA from chromosome 4. Which mutation could have occurred in one of the parental gametes during development to explain both findings?

Answer 1136

Translocation (It’s not an insertion mutation, because an insertion mutation only explains what happened in 21, but not what happened in 4. It’s not a deletion mutation, because a delegation mutation on explains what happened in 4, but not what happened in 21)