Unit 2 (all cards)

Question 1

True or false: Tight junctions function primarily to prevent cells from pulling apart.

Answer 1

False; it’s to keep stuff from getting in

Question 2

The type of secretion where the entire cell dies and the cell fragments are mixed with the produced cellular substance is called a ____ secretion.

Answer 2

holocrine

Question 3

A second degree or “partial thickness burn” is when:

Answer 3

a burn is through the epidermis and part of the dermis.

Question 4

True or false: Fibrosis repairs a tissue and restores the original cells and function of the tissue.

Answer 4

False; Fibrosis replaces damaged tissue mainly with collagen. This does not restore the original function.

Question 5

This tissue is found lining the kidney tubules and functions in absorption and excretion.

Answer 5

simple cuboidal epithelium

Question 6

What tissue comprises tendons and ligaments?

Answer 6

dense regular connective tissue

Question 7

True or false: Hyperplasia is the term for increased cell production in a tissue.

Answer 7

True

Question 8

True or false: Melanin has the greatest influence on your skin tone, but hemoglobin and carotene also contribute to the final tone.

Answer 8

True

Question 9

Sudoriferous glands include what types of glands

Answer 9

Apocrine and merocrine

Question 10

True or false: Merocrine gland secretions are involved in scent communication, not in thermoregulation.

Answer 10

False; that’s apocrine glands. Merocrine glands are involved in thermoregulation.

Question 11

___________________ is the most common but least dangerous type of skin cancer, and occurs in the cells of the stratum basale.

Answer 11

basal cell carcinoma

Question 12

True or false: When looking at the layers of the epidermis, everything superficial to the stratum granulosum is dead.

Answer 12

True

Question 13

Dense irregular connective tissue is found in the ______ layer of the _____.

Answer 13

reticular layer of the dermis

Question 14

Due to the force of muscle contraction and stretching from the loading of blood, heart tissue is under a lot of mechanical stress. Because of this you would not be surprised to learn that cardiac muscle cells are connected by:

Answer 14

desmosomes

Question 15

The growth of bones in length is the result of ____ ossification.

Answer 15

endochondral

Question 16

If you want to lower blood calcium, which hormone(s) will be released?

Answer 16

Calcitonin

Question 17

Because of the action of osteoblasts, which way will calcium ion concentration travel?

Answer 17

from blood to bone

Question 18

To lower blood calcium, which action might a hormone do?

Answer 18

inhibit osteoclast activity

Question 19

True or false: bones of the fingers are an example of long bones

Answer 19

True

Question 20

True or false: Red bone marrow is found in all bones of the adult skeleton.

Answer 20

False; primarily found in the axial skeleton

Question 21

The hardness of bone is thanks to the presence of:

Answer 21

hydroxyapatite and other minerals

Question 22

The most common bone disease/disorder is:

Answer 22

Osteoporosis

Question 23

The uniquely shaped ends of long bones are called the:

Answer 23

epiphyses

Question 24

True or false: The femur of a 5 year old child will have epiphyseal lines.

Answer 24

False; a young child would still have growth plates present.

Question 25

Give an example of a sesamoid bone

Answer 25

Patella

Question 26

The pancreas is located below/behind the stomach. What abdominal quadrant would it mostly belong in?

Answer 26

left upper

Question 27

The pancreas belongs to two different organ systems. It produces important enzymes for breakdown of food, and it produces hormones to regulate our blood glucose. These functions would place it in which two systems?

Answer 27

digestive and endocrine

Question 28

True or false: An epithelial tissue that has multiple layers of cells is more likely to be found in an area where rapid diffusion takes place.

Answer 28

False

Question 29

Where would you find transitional epithelium?

Answer 29

Urinary bladder

Question 30

Which type of tissue is found on the ends of bones in most movable joints?

Answer 30

hyaline cartilage

Question 31

Which type of tissue lines the trachea and bronchi and has cilia and goblet cells?

Answer 31

pseudostratified columnar epithelium

Question 32

What is the tissue that makes up tendons and ligaments?

Answer 32

Dense regular connective tissue

Question 33

What type of tissue is found in the epidermis?

Answer 33

keratinized stratified squamous epithelium

Question 34

Which type of receptor is found in the lower part of the dermis and detects deep touch/pressure and vibration?

Answer 34

lamellar (Pacinian) corpuscles

Question 35

What is the deepest layer of the epidermis?

Answer 35

stratum basale

Question 36

Which layer of the epidermis is composed of the preserved membranes of dead cells?

Answer 36

Stratum corneum

Question 37

What is the difference between thick and thin skin?

Answer 37

The presence of a stratum lucidum

Question 38

Microvilli are folds of the cell membrane that increase the surface area of the cell/tissue. Which tissue has microvilli, and where is it found?

Answer 38

simple columnar, digestive tract

Question 39

Which tissue type has loosely scattered cells and more prominent extracellular matrix?

Answer 39

Connective

Question 40

If you injure a disk in your back, what kind of cartilage has been damaged?

Answer 40

Fibrocartilage

Question 41

In our chapter 7 notes we introduced the idea of feedback loops. Feedback loops enable the body to recognize a change, make a decision about the change, and enact responses. Let's practice recognizing the components of a feedback loop. The healthy pH range of the blood is 7.35-7.45. When you engage in strenuous exercise, muscles remove oxygen from the blood for energy processes, which lowers the blood oxygen level. At the same time, carbon dioxide blood levels climb, which lowers the blood pH. Chemical sensors in blood vessels detect these changes and send feedback to the brainstem. The brain responds by sending a signal to the muscles of respiration for increasing the rate and depth of breathing, which increases the intake of oxygen and the removal of carbon dioxide from the blood. As carbon dioxide is removed from the blood, the pH rises again. In this example of a feedback loop, the effector and stimulus would be:

Answer 41

Effector: the muscles of respiration Stimulus: blood pH and CO2 levels

Question 42

What are the two most durable components of your body?

Answer 42

Bones and teeth (especially the enamel)

Question 43

Do we have a dead or living skeleton?

Answer 43

Living

Question 44

True or false: The skeletal system constantly remodels itself and interacts with other organ systems of the body

Answer 44

True

Question 45

______ is the study of bone

Answer 45

Osteology

Question 46

What are the 3 main components of the skeletal system?

Answer 46

Bones, cartilages, and ligaments

Question 47

Define cartilage, ligaments, and tendons

Answer 47

Cartilage is forerunner of bone formation and coats ends of bones. Ligaments connect bone to bone Tendons connect muscle to bone

Question 48

What are the functions of the skeleton?

Answer 48

Support, protection, movement, electrolyte balance, acid-base balance, and blood formation

Question 49

How does the skeleton aid in support, protection, and movement?

Answer 49

Support: limb bones and vertebrae support body; jaw bone supports teeth; bones support viscera Protection: of brain, spinal cord, heart, lungs etc Movement: of limbs, breathing – action of muscles on bones

Question 50

How does the skeleton aid in maintaining electrolyte and acid base balances, and how does it aid in blood formation?

Answer 50

Electrolyte balance: calcium & phosphate levels Acid–base balance: buffers blood against large pH changes by altering phosphate and carbonate salt levels Blood formation: red bone marrow makes red blood cells

Question 51

Define bone (osseous tissue)

Answer 51

A connective tissue with its matrix hardened by calcium phosphate and other minerals

Question 52

Define mineralization/ calcification

Answer 52

The hardening process of bone

Question 53

What do individual bones consist of?

Answer 53

Individual bones (organs) consist of bone tissue, bone marrow, cartilage, adipose tissue, nervous tissue, and fibrous connective tissue

Question 54

Define sesamoid and sutural bones

Answer 54

Sesamoid (type of short bone) and sutural (wormian) bones Sesamoid bones develop in a tendon (or ligament) in response to a need for more leverage Sutural bones are the extra bones in the sutures (especially the lambdoid suture) of the skull

Question 55

Define compact bone

Answer 55

Has a dense outer shell of bone

Question 56

Define spongy (cancellous) bone

Answer 56

Made up of an internal honeycomb of trabeculae filled with red or yellow bone marrow

Question 57

The skeleton's weight is made up of ___% compact bone and _____% spongy bone

Answer 57

75% compact bone; 25% spongy bone

Question 58

Define diaphysis and epiphyses

Answer 58

Diaphysis—shaft that provides leverage | Epiphyses—enlarged ends of a long bone

Question 59

Define the epiphyseal line (metaphysis) and marrow cavity (medullary cavity)

Answer 59

Epiphyseal line: separates diaphysis from epiphysis (aka metaphysis) Marrow cavity: space in the diaphysis of a long bone that contains bone marrow (aka medullary cavity)

Question 60

Define articular cartilage

Answer 60

A layer of hyaline cartilage that covers joint surface and allows the joint to move more freely

Question 61

Describe the two layers of the periosteum

Answer 61

Outer fibrous layer made of collagen Some fibers continuous with tendons Perforating fibers —penetrate into bone matrix Inner osteogenic layer of bone-forming cells Important to bone growth and healing of fractures

Question 62

Define the periosteum

Answer 62

2 layers covering most of bone

Question 63

Define the endosteum

Answer 63

A thin layer of reticular connective tissue lining marrow cavity Contains osteoblasts and osteoclasts

Question 64

The nutrient foramina is penetrated by what?

Answer 64

Blood vessels

Question 65

Describe the epiphyseal plate (growth plate)

Answer 65

Area of hyaline cartilage that separates epiphyses and diaphyses of children’s bones Enables growth in length When growth is finished turns into Epiphyseal line

Question 66

List the 8 features of long bone

Answer 66

``` Epiphyses Diaphysis Compact bone Spongy bone Marrow cavity Articular cartilage Periosteum Endosteum ```

Question 67

Describe the anatomy of a flat bone

Answer 67

Bones with a sandwich-like structure: two layers of compact bone with a middle layer of spongy bone (diploë)

Question 68

Define and describe the diploë of flat bones

Answer 68

Diploë is the spongy middle layer found in flat bones. It absorbs shock and the marrow spaces are lined with endosteum

Question 69

Define osteogenic cells

Answer 69

Stem cells (cell division) and develop into osteoblasts

Question 70

Define osteoblasts

Answer 70

Bone-forming cells

Question 71

Describe how osteoblasts do their job

Answer 71

Osteoblasts secrete collagen (and other carbohydrate-protein complexes) to form a soft fibrous matrix. This matrix hardens with mineral deposition. They make bone by mitosis and differentiation of osteogenic cells

Question 72

What two organelles are particularly abundant in osteoblasts?

Answer 72

Rough ER and golgi complexes.

Question 73

What stimulates osteogenic cells to multiply rapidly? What does this do?

Answer 73

Stress stimulates osteogenic cells to multiply rapidly, which increases the number of osteoblasts which reinforce bone

Question 74

Define and describe osteocytes

Answer 74

Defined as mature bone cells They're found in pockets called lacunae, and connected to each other by canaliculi and gap junctions Some reabsorb bone matrix & others deposit it; regulates bone remodeling

Question 75

Describe the role of osteocytes when under stress

Answer 75

They act as strain sensors; when stressed, they produce biochemical signals that regulate bone remodeling (shape and density changes that are adaptive)

Question 76

Define and describe osteoclasts

Answer 76

Defined as bone-dissolving cells found on bone surface Derived from fusion of multiple white blood cells (WBC’s) Usually multinucleate Secrete enzymes and acids for the break down of bone (resorption)

Question 77

True or false: Dissolving bone is a part of bone remodeling

Answer 77

True

Question 78

What are the two main parts of the matrix, and what fraction of the matrix do they each make up?

Answer 78

Organic portion (1/3) and inorganic portion (2/3)

Question 79

Describe the organic part of the matrix

Answer 79

Synthesized by osteoblasts Composed of collagen and carbohydrate–protein complexes Responsible for the flexibility of bone Makes up 1/3 of the matrix

Question 80

Describe the inorganic part of the matrix

Answer 80

``` 85% hydroxyapatite (calcium phosphate) 10% calcium carbonate 5% other minerals (fluoride, sodium, potassium, magnesium) Responsible for the hardness of bone Makes up 2/3 of the matrix ```

Question 81

If there is a mineral deficiency, what happens to the bone?

Answer 81

Rickets disease

Question 82

Describe Rickets disease

Answer 82

A disease caused by mineral deficiency and resulting in soft, deformed bones

Question 83

If there is a defect in collagen deposition, what happens to the bone?

Answer 83

Osteogenesis imperfecta (brittle bone disease)

Question 84

Describe osteogenesis imperfecta (brittle bone disease)

Answer 84

Results from a defect in collagen deposition

Question 85

Histology of compact bone reveals that they have _____

Answer 85

Osteons (haversian systems)

Question 86

Describe the 3 elements of the haversian system of an osteon

Answer 86

1) Lamellae Columns of the matrix (mainly collagen) that are weight bearing Run concentric, circumferential, and interstitially 2) Central (Haversian canal) Contains blood vessels and nerves 3) Perforating (Volkmann’s) canals Channels that connect blood and nerves from periosteum to the central (Haversian) canal

Question 87

Describe lamellae in osteons

Answer 87

Columns of the matrix (mainly collagen) that are weight bearing. The columns run concentric, circumferential, and interstitially

Question 88

Describe the central (Haversian) canal of the osteon

Answer 88

Contains blood vessels and nerves

Question 89

Describe the perforating (volkmann's) canals of osteons

Answer 89

Channels that connect blood and nerves from periosteum to the central (Haversian) canal Run transverse or diagonal

Question 90

Where do trabeculae develop in spongy bone?

Answer 90

They develop along the bone’s lines of stress

Question 91

Something described as a "lattice of bone covered with endosteum" is known as what?

Answer 91

Spongy bone

Question 92

Describe the structure and function of spongy bone

Answer 92

Structure: It's a lattice of bone covered with endosteum; made up of trabeculae (thin plates of bone) that develop along the bone's lines of stress, and the spaces are filled with red bone marrow. Has few osteons and no central canals Function: Provide strength with minimal weight

Question 93

Define bone marrow

Answer 93

Soft tissue occupying marrow cavities of long bones and small spaces of spongy bone

Question 94

What are the two types of bone marrow?

Answer 94

Yellow and red

Question 95

Describe red bone marrow

Answer 95

- Contains hemopoietic tissue—produces blood cells - Found in nearly every bone in a child - In adults, it's found in the skull, vertebrae, ribs, sternum, part of pelvic girdle, and proximal heads of humerus and femur

Question 96

Describe yellow bone marrow

Answer 96

- Found in adults - Stores Triglycerides - Can transform back to red marrow in the event of chronic anemia

Question 97

Describe where red bone marrow is found in children and adults

Answer 97

Infants – in nearly every bone 1. medullary cavity 2. all areas of spongy bone Adults 1. head of the femur and humerus 2. diploë (spongy bone) of flat bones 3. some irregular bones (such as hip and vertebrae)

Question 98

Define ossification or osteogenesis

Answer 98

The formation of bone

Question 99

In the human fetus and infant, bone develops by what two methods?

Answer 99

Intramembranous ossification | Endochondral ossification

Question 100

When does intramembranous ossification occur?

Answer 100

It produces the flat bones of skull and clavicle in fetuses (and ossifies the fontanels, and thickens long bones throughout life)

Question 101

During intramembranous ossification, bone develops within what kind of membrane?D

Answer 101

A fibrous connective tissue membrane

Question 102

Describe the life-cycle of an osteocyte formed by intramembranous ossification

Answer 102

Mesenchymal cells turn into osteoblasts which turn into osteocytes (spongy bone)

Question 103

Describe intramembranous ossification

Answer 103

Bone develops within a fibrous connective tissue membrane (Mesenchymal cells to osteoblasts to osteocytes (spongy bone)) Forms the flat bones of the skull, clavicles, and ossifies the fontanels. Most of these bones are remodeled (destroyed and reformed) as we grow to adult size.

Question 104

Describe endochondral ossification

Answer 104

Bone forms by replacing hyaline cartilage Forms most the bones of the body below the skull (except the clavicle) Mesenchyme turn into chondroblasts, which die and are replaced by osteoblasts, which form spongy bone, which forms compact bone

Question 105

What type of ossification is best described as "bone is formed by replacing hyaline cartilage"?

Answer 105

Endochondral ossification

Question 106

In endochondral ossification, what do primary and secondary ossification form?

Answer 106

Primary Ossification: forms diaphysis | Secondary ossification: forms epiphysis

Question 107

When do epiphyseal plates close? What does this mean for growth?

Answer 107

Close in late teens to early 20s, which is when bone can no longer grow in length

Question 108

During infancy and childhood, in endochondral ossification the epiphyses fill with _______ bone

Answer 108

spongy

Question 109

Describe the role of cartilage in endochondral ossification

Answer 109

Cartilage is limited to the articular cartilage covering each joint surface, and to the epiphyseal plate

Question 110

Describe the role of the epiphyseal plate in bone growth

Answer 110

Serves as a growth zone for bone elongation, covered with cartilage

Question 111

True or false: bones grow in two directions, which are length and width

Answer 111

True

Question 112

True or false: Ossification continues throughout life with the growth and remodeling of bones

Answer 112

True

Question 113

Describe how bones grow in length

Answer 113

Occurs at Epiphyseal plates Cartilage cells undergo mitosis, pushing the epiphysis away from the diaphysis Cartilage cells die and are replaced by bone. When growth is finished, there's no more cartilage at the plate, which then becomes an epiphyseal line, and bone can no longer grow in length

Question 114

Describe achondroplastic dwarfism

Answer 114

Long bones stop growing in childhood Normal torso, short limbs Failure of cartilage growth in metaphysis Spontaneous mutation produces mutant dominant allele

Question 115

Describe pituitary dwarfism

Answer 115

Lack of growth hormone | Normal proportions with short stature

Question 116

Describe how bones become wider/thicker

Answer 116

Happens through appositional growth: continual growth in diameter and thickness throughout the lifespan through intramembranous ossification. Osteoblasts of inner periosteum deposit osteoid tissue Lay down matrix in layers parallel to surface Forms circumferential lamellae Osteoclasts of endosteum enlarge marrow cavity

Question 117

Define appositional growth and where it happens

Answer 117

The growth of bone horizontally; happens on the surface of bone

Question 118

About ___% of an adult's skeleton is remodeled each year

Answer 118

10%

Question 119

What are the two main types of cells involved in bone remodelling?

Answer 119

Osteoblasts: Bone deposition Osteoclasts: Bone resorption

Question 120

Describe Wolff's Law of Bone

Answer 120

Bone grows or remodels in response to the demands placed on it Exercise: promotes bone growth Lack of exercise (bedridden): atrophies bones

Question 121

Define mineral deposition/ mineralization

Answer 121

The process in which calcium, phosphate, and other ions are taken from blood and deposited in bone

Question 122

Describe the process of mineral deposition/ mineralization

Answer 122

Osteoblasts produce collagen fibers Fibers become encrusted with minerals First few crystals act as seed crystals that attract more calcium and phosphate Abnormal calcification (ectopic ossification) Formation of a calculus (calcified mass) in lung, brain, eye, muscle, tendon, or artery (arteriosclerosis)

Question 123

Define mineral reabsorption

Answer 123

The process of dissolving bone and releasing minerals into blood

Question 124

Describe the process of mineral reabsorption

Answer 124

Performed by osteoclasts Pump hydrogen to extracellular fluid (chloride follows). Hydrochloric acid (pH 4) dissolves bone minerals Produce an enzyme which digests collagen in an acidic environment

Question 125

Describe the role of osteoclasts and osteoblasts in braces

Answer 125

Braces reposition teeth, which move because osteoclasts dissolve bone ahead of the tooth; osteoblasts deposit bone behind the tooth

Question 126

Describe the role of the bone matrix in homeostasis

Answer 126

Minerals are deposited in the skeleton and withdrawn from the skeleton when they are needed for other purposes Phosphate is a component of DNA, RNA, ATP, phospholipids, and pH buffers Calcium needed in neuron communication, muscle contraction, blood clotting, and exocytosis

Question 127

What is phosphate a component of?

Answer 127

DNA, RNA, ATP, phospholipids, and pH buffers

Question 128

What is calcium needed for in the body?

Answer 128

Neuron communication, muscle contraction, blood clotting, and exocytosis

Question 129

True or false: Calcium and phosphate are used for much more than bone structure

Answer 129

True

Question 130

Define homeostasis

Answer 130

The ability to detect change, activate mechanisms that oppose it, and thereby maintain relatively stable internal conditions

Question 131

Describe negative feedback

Answer 131

It allows for a dynamic equilibrium within a limited range around a set point. The body senses a change and “negates” or reverses it. The fundamental mechanism to keep body in homeostasis.

Question 132

Loss of homeostatic control causes what?

Answer 132

Illness or death

Question 133

Why are feedback loops called feedback loops?

Answer 133

Because feedback mechanisms alter the original changes that triggered them, they are called feedback loops.

Question 134

Describe the role of homeostasis in body temperature

Answer 134

If too warm, vessels dilate in the skin and sweating begins (heat-losing mechanism). If too cold, vessels in the skin constrict and shivering begins (heat-gaining mechanism).

Question 135

What are the 3 main components of feedback loops?

Answer 135

Receptor, integration (control) center, and effector.

Question 136

Define a receptor in feedback loops

Answer 136

Structure that senses change in the body (chemical, temperature, pain, pressure, volume, etc.)

Question 137

Define an integration (control) center in a feedback loop

Answer 137

The control center that processes the sensory information, “makes a decision,” and directs the response (e.g., cardiac center of the brain)

Question 138

Define an effector in a feedback loop

Answer 138

The cell or organ that carries out the final corrective action to restore homeostasis (e.g., the heart)

Question 139

Define and describe positive feedback loops

Answer 139

It's a self-amplifying cycle that leads to greater change in the same direction; the feedback loop is repeated (change produces more change). It's a normal way of producing rapid changes (ex: childbirth, blood clotting, protein digestion, and generation of nerve signals) However, they can sometimes be dangerous (ex: the vicious cycle of runaway fever)

Question 140

Calcium homeostasis depends on a balance between what two things?

Answer 140

Intake (diet) and loss (urinary and fecal eliminations)

Question 141

How is calcium homeostasis maintained?

Answer 141

By calcium exchange between osseous tissue and blood, which is mediated by three hormones

Question 142

Calcium homeostasis is regulated by what three hormones?

Answer 142

Calcitriol (vitamin D), calcitonin, and parathyroid hormone

Question 143

Describe the role of calcitriol (vitamin D) in calcium homeostasis

Answer 143

It raises blood calcium levels; mainly, it increases calcium absorption by small intestine, and it also increases calcium resorption from the skeleton. It weakly promotes kidney reabsorption of calcium ions, so less is lost in urine Produced by actions of skin, liver, and kidneys

Question 144

What is calcitriol (vitamin d) needed for in the body? What does a calcitriol deficiency result in?

Answer 144

Calcitriol is necessary for bone deposition; lack of calcitriol results in abnormal softness of bones. In children, a deficiency results in rickets. In adults, a deficiency results in osteomalacia

Question 145

Describe the role of calcitonin in calcium homeostasis

Answer 145

Produced by the thyroid gland Its release is triggered by high blood calcium, and it lowers blood calcium concentration in 2 ways: Inhibits osteoclasts and stimulates osteoblasts Important in children, weak effect in adults (except may inhibit bone loss in pregnant and lactating women)

Question 146

What increases blood calcium? What decreases blood calcium?

Answer 146

Calcitriol (vitamin D) and parathyroid hormone increase blood calcium; calcitonin decreases blood calcium

Question 147

Describe the role of parathyroid hormone in calcium homeostasis

Answer 147

PTH increases blood calcium 4 ways: 1) Stimulates osteoclast population and bone resorption 2) Promotes calcium reabsorption by kidneys 3) Promotes calcitriol synthesis 4) Inhibits osteoblasts, inhibiting bone deposition Produced by parathyroid glands Release triggered by low blood calcium

Question 148

Describe the causes and effects of hypocalcemia

Answer 148

Effects: causes overly excitable nervous system and tetany (muscle spasms) (laryngospasm) Some cases are caused by vitamin D deficiency or underactive parathyroid glands Pregnancy and lactation increase risk of hypocalcemia

Question 149

Define hypocalcemia and hypercalcemia

Answer 149

Hypocalcemia: low blood calcium. Hypercalcemia: high blood calcium.

Question 150

Describe the causes and effects of hypercalcemia

Answer 150

Makes nerve and muscles less excitable Can cause emotional disturbance, muscle weakness, sluggish reflexes, cardiac arrest Hypercalcemia rarely occurs

Question 151

Describe bone development from infancy to early adulthood

Answer 151

Infancy and childhood: epiphyseal plate activity is stimulated by Human Growth Hormone (hGH) Puberty: (testosterone and estrogens) promotes adolescent growth spurts and differentiates the male/female skeleton; bone growth ends (18 - 21 years)

Question 152

At least __ or more hormones, vitamins, and growth factors affect osseous tissue

Answer 152

At least 20 or more hormones, vitamins, and growth factors affect osseous tissue

Question 153

Why do girls grow faster than boys and reach full height earlier?

Answer 153

Estrogen has stronger effect than testosterone on bone growth

Question 154

Describe the effects of anabolic steroids on growth

Answer 154

Causes bone growth to stop and the epiphyseal plate to “close” prematurely Results in abnormally short adult stature

Question 155

Define a stress fracture

Answer 155

A break caused by abnormal trauma to a bone

Question 156

Define a pathological fracture

Answer 156

A break in bone that's been weakened by disease (cancer or osteoporosis)

Question 157

Fractures are classified by their structural characteristics; what are they?

Answer 157

Displaced vs nondisplaced | Open vs closed

Question 158

Define closed reduction

Answer 158

A procedure to treat fractures in which bone fragments are manipulated into their normal positions without surgery

Question 159

Define open reduction

Answer 159

A procedure to treat fractures that involves surgical exposure of the bone and the use of plates, screws, or pins to realign the fragments

Question 160

Define a cast

Answer 160

Normally used to stabilize and immobilize healing bone

Question 161

Describe osteoporosis

Answer 161

The most common bone disease Affects spongy bone the most since it is the most metabolically active Subject to pathological fractures of hip, wrist, and vertebral column Kyphosis (widow’s hump)—deformity of spine due to vertebral bone loss Complications of loss of mobility are pneumonia and thrombosis

Question 162

The most common bone disease is __________

Answer 162

osteoporosis

Question 163

What is kyphosis and why does it happen?

Answer 163

It's a deformity of the spine due to vertebral bone loss

Question 164

What demographics are most likely to get osteoporosis?

Answer 164

- Estrogen maintains bone density in both sexes; inhibits resorption by osteoclasts - Postmenopausal white women at greatest risk; this is because white women begin to lose bone mass as early as age 35 and By 70, average loss is 30% of bone mass - Osteoporosis also seen in young female athletes with low body fat causing them to stop ovulating and decrease estrogen secretion - Risk factors: race, age, gender, smoking, diabetes mellitus, diets poor which are poor in: calcium, protein, vitamins C and

Question 165

What are the treatments for osteoporosis?

Answer 165

- Estrogen replacement therapy (ERT) (slows bone resorption, but increases risk of breast cancer, stroke, and heart disease) - Certain medications destroy osteoclasts - Best treatment is prevention: exercise and a good bone-building diet between ages 25 and 40

Question 166

True or false: Inspection of the skin, hair, and nails is significant part of a physical exam

Answer 166

True

Question 167

True or false: Skin is NOT the most vulnerable organ

Answer 167

False; skin is the most vulnerable organ. It's exposed to radiation, trauma, infection, and injurious chemicals

Question 168

True or false: the skin receives more medical treatment than any other organ system

Answer 168

True

Question 169

Define dermatology

Answer 169

The scientific study and medical treatment of the integumentary system

Question 170

What are the six main functions of the skin?

Answer 170

``` 1) Resistance to trauma and infection: Keratin; dermacidin & defensins; acid mantle 2) Other barrier functions: Water (protects against dehydration) UV radiation; melanin Harmful chemicals 3) Vitamin D synthesis: Skin carries out first step; Liver & kidneys complete process 4) Sensation receptors Touch, temperature, pressure, vibration, tickle, itch, and pain sensations 5) Regulation of body temperature Thermoreceptors Vasoconstriction/vasodilation If you are too warm, do cutaneous blood vessels vasodilate or vasoconstrict? Perspiration 6) Nonverbal communication ```

Question 171

What are the two layers of the skin (cutaneous membrane)?

Answer 171

Dermis and epidermis

Question 172

What are the two main parts of the skin?

Answer 172

The cutaneous membrane (the skin) and the subcutaneous layer

Question 173

What type of cells is the epidermis made of?

Answer 173

Keratinized stratified squamous epithelium

Question 174

Describe the characteristics of the epidermis

Answer 174

Includes dead cells at skin surface packed with tough keratin protein 5 distinct strata (layers) in thick skin; 4 strata in thin skin Lacks blood vessels Depends on the diffusion of nutrients from underlying connective tissue Contains sparse nerve endings for touch and pain

Question 175

List the five epidermal cell types

Answer 175

Stem cells, keratinocytes, melanocytes, tactile (merkel) cells, and dendritic cells

Question 176

Describe stem cells in the epidermis

Answer 176

Undifferentiated cells that give rise to keratinocytes | In deepest layer of epidermis (stratum basale)

Question 177

Describe keratinocytes

Answer 177

The majority of epidermal cells; Synthesize keratin

Question 178

Describe melanocytes

Answer 178

Synthesize pigment melanin (shields DNA from UV radiation) | Occur only in stratum basale but have branched processes that distribute melanin to keratinocytes

Question 179

Describe tactile (merkel) cells

Answer 179

Touch receptor cells in basal layer

Question 180

Describe dendritic cells

Answer 180

Macrophages (WBCs) that are part of the immune system | Found mainly in stratum spinosum and granulosum

Question 181

Describe thick skin and where it's found

Answer 181

Lacks hair follicles and sebaceous (oil) glands Has stratum lucidum Generally has more sweat and sensory receptors Epidermis 0.5 mm thick Found on palms of hands and soles of feet

Question 182

Describe thin skin

Answer 182

Possesses hair follicles, sebaceous glands, and sweat glands | Epidermis about 0.1 mm thick

Question 183

Name the layers of the epidermis from deepest to shallowest

Answer 183

Stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum

Question 184

Describe the stratum basale

Answer 184

Single layer of stem cells and keratinocytes Stem cells divide and give rise to keratinocytes that migrate toward skin surface to replace lost cells Also contains a few melanocytes and tactile cells Deepest epidermal layer

Question 185

Describe the stratum spinosum

Answer 185

Several layers of keratinocytes joined together by desmosomes and tight junctions Named for appearance of cells after histological preparation (spiny) Also contains some dendritic cells

Question 186

Describe the stratum granulosum

Answer 186

Three to five layers of flat keratinocytes | Cells contain dark-staining kerotohyalin granules

Question 187

Describe the stratum lucidum

Answer 187

Thin, pale layer found only in thick skin

Question 188

Describe the stratum corneum

Answer 188

20-30 layers of dead, scaly, keratinized cells | Resists abrasion, water loss, penetration of bacteria and chemicals

Question 189

Describe the life history of a keratinocyte

Answer 189

Stem cells divide producing keratinocytes. New keratinocytes push older ones toward the surface Over time, keratinocytes flatten, produce more keratin and membrane-coating vesicles that release lipids that waterproofs the cell.

Question 190

How long does it take keratinocytes to reach the surface layer of skin?

Answer 190

Take about 30-40 days – slower in old age and faster in injured or stressed skin (calluses or corns).

Question 191

Where does mitosis occur in keratinocytes?

Answer 191

Keratinocytes in the deepest part of stratum spinosum can also divide. Mitosis requires abundant oxygen and nutrients, so once cells migrate away from blood vessels of the dermis, mitosis cannot occur

Question 192

Describe the function of the epidermal water barrier

Answer 192

Water retention is fostered by tight junctions between skin cells and the waterproofing that occurs in the stratum granulosum Helps prevent dehydration Does not prevent the absorption of water by the stratum corneum when we soak in a bath (“prune fingers”)

Question 193

What are the layers of the dermis? (in order from shallow to deep)

Answer 193

Papillary layer and reticular layer

Question 194

Describe the papillary layer of the dermis

Answer 194

Most superficial layer of the dermis Thin zone of areolar tissue in and near the dermal papilla Anchors epidermis to dermis Rich in small blood vessels Contains Tactile (Meissner) corpuscles (touch) and free nerve endings (pain and temperature)

Question 195

Describe the reticular layer of the dermis

Answer 195

The deeper and thicker layer of dermis Consists of dense, irregular connective tissue Packed with oil glands, sweat glands, hair follicles, etc. Stretch marks (striae): tears in the collagen fibers caused by stretching of the skin due to pregnancy or obesity Contains Lamellar (Pacinian) corpuscles for pressure reception

Question 196

Describe the formation of fingerprints

Answer 196

Dermal papillae are more pronounced in thick skin (palms, soles, etc.) As epidermis conforms to papillae, epidermal ridges are formed Increases friction – better grip

Question 197

Describe the hypodermis

Answer 197

Has more areolar and adipose than dermis Common site of drug injection since it has many blood vessels Subcutaneous fat used for energy reservoir and thermal insulation Thicker in women Thinner in infants and elderly

Question 198

Describe the 3 main things that contribute to skin color

Answer 198

1) Melanin Produced by melanocytes, accumulates in keratinocytes People of different skin colors have the same number of melanocytes but differ on the amounts of melanin 2) Hemoglobin pigment in red blood cells; adds reddish to pinkish hue to skin 3) Carotene yellow pigment acquired from egg yolks and yellow/orange vegetables Concentrates in stratum corneum and subcutaneous fat

Question 199

Describe melanin

Answer 199

Eumelanin—brownish black Pheomelanin—reddish yellow (sulfur-containing) Darker skinned people: Produce greater quantities of melanin Melanin breaks down more slowly Melanin granules more spread out in keratinocytes Melanized cells seen throughout the epidermis Lighter skinned people: Melanin clumped near keratinocyte nucleus Little melanin seen beyond stratum basale Exposure to UV light stimulates melanin secretion and darkens skin This color fades as melanin is degraded and old cells are exfoliated

Question 200

List the different types of skin color/tone and describe what conditions are associated with them

Answer 200

Cyanosis—blueness due to oxygen deficiency Erythema—redness due to increased blood flow to skin Pallor—paleness due to decreased blood flow to skin Albinism—milky white skin and blue-gray eyes due to genetic lack of melanin synthesizing enzyme Jaundice—yellowing due to bilirubin in blood (can be caused by compromised liver function) Hematoma—bruising (clotted blood under skin

Question 201

Define hair

Answer 201

A slender filament of keratinized cells growing from a tube in the skin called a hair follicle

Question 202

What are the 3 sections of a hair along its length?

Answer 202

Bulb: Contains matrix cells (mitotically active cells) Root: the remainder of the hair in the follicle Shaft: the portion above the skin surface

Question 203

What are the three layers of a hair visible in a cross-section?

Answer 203

Medulla (core), Cortex, Cuticle (outer layer)

Question 204

Describe hair receptors

Answer 204

sensory nerve fibers entwining follicles | Detect hair movement

Question 205

Describe the piloerector muscle (arrector pili)

Answer 205

Smooth muscle attaching follicle to dermis | Contracts to make hair stand on end (goose bumps)

Question 206

What are the 4 main functions of hair?

Answer 206

Protection Light touch Heat retention Excretion

Question 207

Describe the composition of fingernails

Answer 207

They're clear, hard derivatives of stratum corneum composed of thin, dead cells packed with hard keratin

Question 208

Describe merocrine/eccrine sweat glands

Answer 208

Most numerous of skin glands Duct opens to surface of skin Regulates body temperature with perspiration

Question 209

Describe apocrine sweat glands

Answer 209

Locations: groin, anal region, axilla, areola, beard (men) Inactive until puberty; responds to stress and sexual stimulation Ducts lead to nearby hair follicles Believed to secrete pheromones

Question 210

Define bromhidrosis

Answer 210

Disagreeable body odor produced by bacterial action on sweat from apocrine glands

Question 211

Describe sebaceous glands

Answer 211

Most open into a hair follicle, and they utilize a holocrine secretion style to secrete sebum

Question 212

Describe sebum

Answer 212

The oily secretion of sebaceous glands Keeps skin and hair from becoming dry, brittle, and cracked Inhibits growth of bacteria & fungi (ringworm)

Question 213

Give an example of a modified oil gland

Answer 213

Ciliary Glands

Question 214

Describe the ceruminous glands in external ear canal

Answer 214

``` Modified apocrine glands Forms earwax (cerumen) ```

Question 215

Describe mammary glands

Answer 215

Milk-producing glands that develop only during pregnancy. Modified apocrine sweat glands Rich secretion released through ducts opening at nipple

Question 216

What causes most skin cancers?

Answer 216

Most cases caused by UV rays of the sun damaging skin cell DNA

Question 217

What are the three types of skin cancer? Describe their malignancy

Answer 217

``` 1) Basal cell carcinoma Most common but least malignant 2) Squamous cell carcinoma May metastasize if not removed 3) Melanoma Least common but very malignant ```

Question 218

Describe basal cell carcinomas

Answer 218

Most common type Least dangerous because it seldom metastasizes Forms from cells in stratum basale Lesion is small, shiny bump with central depression and beaded edges

Question 219

Describe squamous cell carcinoma

Answer 219

- Arises from keratinocytes of stratum spinosum - Lesions usually on scalp, ears, lower lip, or back of the hand - Have raised, reddened, scaly appearance later forming a concave ulcer - Chance of recovery good with early detection and surgical removal - Tends to metastasize to lymph nodes and may become lethal

Question 220

Describe malignant melanoma

Answer 220

Skin cancer that arises from melanocytes Less than 5% of skin cancers, but most deadly form Can be successfully removed if caught early, but if it metastasizes it is usually fatal Greatest risk factor: familial history of malignant melanoma Highest incidence in men, redheads, and people who had severe sunburn as a child

Question 221

List the ABCDEs of melanomas

Answer 221

``` A: Asymmetry B: Border C: Color D: Diameter E: Elevation and/or evolution ```

Question 222

Describe burns

Answer 222

The leading cause of accidental death Fires, kitchen spills, sunlight, ionizing radiation, strong acids or bases, or electrical shock Deaths result primarily from fluid loss, infection, and toxic effects of eschar (burned, dead tissue) Debridement: removal of eschar Burns classified according to depth of tissue involvement

Question 223

Describe first degree burns

Answer 223

Involves only epidermis; Heals in days

Question 224

Describe second degree burns

Answer 224

Partial-thickness burn; involves part of dermis May appear red, tan, or white; blistered and painful Two weeks to several months to heal and may leave scars

Question 225

Describe third degree burns

Answer 225

Full-thickness burn; involves epidermis, all of dermis, and often some deeper tissues Often requires skin grafts Needs fluid replacement, infection control, supplemental nutrition

Question 226

The tissue found covering body surfaces, lining body cavities, forming the internal and external linings of many organs, and constituting most gland tissue is _____ tissue

Answer 226

epithelial

Question 227

``` Which term is used to describe the free surface of an epithelium? Apical Basal Open Medullary ```

Answer 227

Apical

Question 228

``` Which epithelium lines the respiratory tract from the nasal cavity to the bronchi? Simple cuboidal Transitional Simple columnar Pseudostratified columnar ```

Answer 228

Pseudostratified columnar

Question 229

Which surface of an epithelial cell faces the basement membrane? Basal Apical

Answer 229

Basal

Question 230

``` Which epithelium has tall columnar cells in a single layer interspersed with shorter basal cells and nuclei at varying levels? Stratified columnar Stratified squamous Pseudostratified columnar Simple cuboidal ```

Answer 230

Pseudostratified columnar

Question 231

``` What is the function of transitional epithelium? To allow stretching To absorb nutrients To move fluid through tubules To protect against abrasion ```

Answer 231

To allow stretching

Question 232

``` Which epithelium forms glandular epithelium and lines the kidney tubules? Simple cuboidal Pseudostratified columnar Stratified columnar Simple squamous ```

Answer 232

Simple cuboidal

Question 233

``` Which epithelium is best suited for resisting abrasion and preventing pathogen entry into deeper tissues? Areolar Dense regular Stratified squamous Simple cuboidal ```

Answer 233

Stratified squamous

Question 234

``` Which are functions of connective tissue in the body? (more than one correct answer) Absorption Support and protect organs Bind organs to one another Communication ```

Answer 234

Support and protect organs | Bind organs to one another

Question 235

``` Which cells found in connective tissue engulf foreign particles, activate the immune system, and destroy dead or dying cells? Adipocytes Macrophages Reticulocytes Chondroblasts Fibroblasts ```

Answer 235

Macrophages

Question 236

``` Where would transitional epithelium be found? Lining the lumen of an artery Lining the lumen of a kidney tubule Lining the lumen of the urinary bladder Lining the lumen of the small intestine ```

Answer 236

Lining the lumen of the urinary bladder

Question 237

``` While preparing some chicken wings for cooking you observe white fibers connecting the bones and the muscles to bone. What type of fibers are these? Elastic Reticular Collagenous Myosin ```

Answer 237

Collagenous

Question 238

``` Stratified ______ epithelium is the most widespread epithelium of the body. cuboidal columnar squamous transitional ```

Answer 238

squamous

Question 239

``` Which tissue class supports and binds tissues together? Nervous Epithelial Connective Muscular ```

Answer 239

Connective

Question 240

What are the functions of macrophages? (multiple select question) They engulf foreign particles. They transport nutrients in the blood and lymph fluid. They produce fibers and ground substance. They destroy dead or dying self cells. They activate the immune system when they encounter antigens.

Answer 240

They engulf foreign particles. They destroy dead or dying self cells. They activate the immune system when they encounter antigens.

Question 241

``` What are the three fiber types found in fibrous connective tissue? Intermediate Elastic Reticular Collagenous Actin Myosin ```

Answer 241

Elastic Reticular Collagenous

Question 242

____ cartilage is found in the esophagus

Answer 242

hyaline

Question 243

Cartilage in the outer ear is ______. hyaline cartilage fibrocartilage elastic cartilage

Answer 243

elastic cartilage

Question 244

``` The type of connective tissue found beneath the skin, within the breast, and on the surface of the heart is ______ tissue. osseous adipose dense regular cartilage ```

Answer 244

adipose

Question 245

The top of the outer ear (where you get helix piercings) is made of ____ cartilage

Answer 245

elastic

Question 246

``` What is another name for the axon of a neuron? Dendrite Nerve fiber Neurosoma Neuroglia ```

Answer 246

Nerve fiber

Question 247

``` Which part of a neuron receives incoming signals from other cells? Fiber Axon Dendrite Neurosoma ```

Answer 247

Dendrite

Question 248

Skin is an example of a(n) _____ membrane.

Answer 248

cutaneous

Question 249

The membranes lining the inside surface of the respiratory and digestive tracts are examples of _______ membranes.

Answer 249

mucous

Question 250

Which of the following best describes tight junctions? They consist of transmembrane cell-adhesion proteins around the upper part of a cell and hold neighboring cells together. They consist of the membrane plaques of adjacent cells anchored together; there is a space between cell membranes. They consist of connexons surrounding a channel leading from one cell to its neighbor.

Answer 250

They consist of transmembrane cell-adhesion proteins around the upper part of a cell and hold neighboring cells together.

Question 251

The abdominal cavity is lined with a ____ membrane.

Answer 251

serous

Question 252

What are the three main types of body membranes?

Answer 252

Mucous, serous, and cutaneous

Question 253

The acid ______ is the protective film that gives skin its slight acidity.

Answer 253

mantle

Question 254

``` Which term refers to the protective film found on skin that is involved in bacterial protection? Fungi colonization Antibiotics Acid microbes Acid mantle ```

Answer 254

Acid mantle

Question 255

Skin is classified as thick or thin based on the thickness of which layer?

Answer 255

Stratum corneum

Question 256

What event occurs to preserve heat in the body?

Answer 256

Vasoconstriction of blood vessels in the skin

Question 257

``` Which of the following are functions of the skin? ((Multiple select question.)) Vitamin C synthesis Vitamin D synthesis Sensory reception Thermoregulation ```

Answer 257

Vitamin D synthesis Sensory reception Thermoregulation

Question 258

Which of the following are features of skin that minimize bacterial and fungal growth during an infection. ((Multiple select question.)) The dryness of the skin inhibits microbial growth. The cells of the skin shed infrequently. The acid mantle inhibits microbial growth. Vitamins secreted through the pores inhibits microbial growth.

Answer 258

The dryness of the skin inhibits microbial growth. | The cells of the skin shed infrequently.

Question 259

The five types of cells found in the epidermis are:

Answer 259

Stem cells, keratinocytes, tactile cells, dendritic cells, and melanocytes

Question 260

``` Cells in the epidermis are nourished by blood vessels located in which of the following? Hyperdermis Dermis Subdermis Hypodermis ```

Answer 260

Dermis

Question 261

Which of the following are located in the dermis? Simple cuboidal epithelium and mast cells Fat and loose connective tissue Melanocytes and Langerhans cells Fibers, glands, blood vessels and nerve endings

Answer 261

Fibers, glands, blood vessels and nerve endings

Question 262

``` Which term refers to the wavy upward projections at the boundary of the dermis and epidermis? Areolae Striae Dermal papillae Reticular layers ```

Answer 262

Dermal papillae

Question 263

The deepest layer of the dermis is called the _____ layer.

Answer 263

reticular

Question 264

Why are injections frequently administered into the hypodermis?

Answer 264

The subcutaneous tissue is highly vascular.

Question 265

Define dendritic cells

Answer 265

Immune cells that guards against pathogens that penetrate into the skin

Question 266

Define tactile cells

Answer 266

Sensory receptors for touch

Question 267

What are the two zones of the dermis?

Answer 267

Papillary and reticular layer

Question 268

_____ is a word that means "abnormal redness of the skin."

Answer 268

Erythema

Question 269

``` What usually causes a hematoma? Blows to the skin Exposure to cold temperatures Abrasion from rough surfaces Hot water spills on the skin ```

Answer 269

Blows to the skin

Question 270

``` Fingernails and toenails are derivatives of which epidermal layer? Stratum corneum Stratum lucidum Stratum granulosum Stratum basale ```

Answer 270

Stratum corneum

Question 271

Which substance, excreted by the liver, can accumulate to cause jaundice?

Answer 271

Bilirubin

Question 272

``` Which type of sweat gland has a duct that opens by way of a pore on the skin surface? Sebaceous gland Ceruminous gland Apocrine sweat gland Merocrine sweat gland ```

Answer 272

Merocrine sweat gland

Question 273

``` Most tumors occur where exposure to the sun is greatest. These areas would include which of the following? Legs, brain, stomach Stomach, head, heart Head, neck, and hands Scalp, arm, knee ```

Answer 273

Head, neck, and hands

Question 274

``` James has a small shiny lesion that develops a central depression that has not invaded the dermis. A biopsy will most likely show that he has which of the following? Surface melanoma Melanoma Basal cell carcinoma Lymphoma ```

Answer 274

Basal cell carcinoma

Question 275

The three types of skin cancer can be distinguished from each other by which of the following? Zones of tissue injury and the ability to synthesize melanin Appearance of their lesions and zones of tissue injury Appearance of their lesion and ability to synthesize melanin Degree of redness and number of remaining keratinocytes

Answer 275

Appearance of their lesions and zones of tissue injury

Question 276

``` Lilly goes to the beach 3 times a week to tan. She develops a lesion on her scalp and ears that later form concave ulcers with raised edges. Lilly most likely has which of the following? Lymphoma Basal cell carcinoma Squamous cell carcinoma Melanoma ```

Answer 276

Squamous cell carcinoma

Question 277

The study of bone is called ______

Answer 277

osteology

Question 278

``` What is the major producer of blood cells? Carbonate salts Red bone marrow Compact bone Calcium cells ```

Answer 278

Red bone marrow

Question 279

The process in which dense regular connective tissue hardens to form bone is called _____

Answer 279

ossification

Question 280

Bones are classified as one of four types based on their shape. The bones of the cranium are examples of _____ bones

Answer 280

flat

Question 281

Bones such as the vertebrae are classified as _____ bones

Answer 281

irregular

Question 282

One function of the skeleton is to store calcium and phosphate to help maintain _______ balance

Answer 282

electrolyte

Question 283

``` What is the deposition of calcium salts called? Osteomalacia Ossification Calcification Resorption ```

Answer 283

Calcification

Question 284

Bones such as the carpals that have the same length and width are classified as _____ bones.

Answer 284

short

Question 285

``` Thin, often curved, bones are classified as what shape? Irregular Short Flat Long ```

Answer 285

Flat

Question 286

``` What is the expanded end of a long bone to which tendons and ligaments attach called? Metaphysis Diaphysis Epiphysis Epiphyseal plate ```

Answer 286

Epiphysis

Question 287

Bones that are longer than they are wide are classified as ______ bones.

Answer 287

long

Question 288

The shaft of a long bone is called the _____

Answer 288

diaphysis

Question 289

Which allows the passage of blood vessels into a bone? Perforating canal Nutrient foramen Central canal

Answer 289

Nutrient foramen

Question 290

Which describes the structure of a flat bone? A layer of compact bone is sandwiched between two layers of spongy bone. A layer of spongy bone is sandwiched between two layers of compact bone.

Answer 290

A layer of spongy bone is sandwiched between two layers of compact bone.

Question 291

``` An epiphyseal line is slightly denser ______. spongy bone periosteum compact bone cartilage ```

Answer 291

spongy bone

Question 292

``` Which bone cells produce the organic bone matrix? Osteoclasts Osteoblasts Chondrocytes Osteocytes ```

Answer 292

Osteoblasts

Question 293

What is the hyaline cartilage found covering the ends of bones within a joint called?

Answer 293

Articular cartilage

Question 294

What is the term for the bone tissue located between the two layers of compact bone in the skull?

Answer 294

Diploe

Question 295

The action carried out by osteoclasts is called ______.

Answer 295

osteolysis

Question 296

The protein and carbohydrate portion of bone matrix forms the ______ matter.

Answer 296

organic

Question 297

``` Within compact bone, a central canal is found at the center of which structure? A bone An epiphysis A Volkmann canal An osteon ```

Answer 297

An osteon

Question 298

Which structures found in spongy bone line up along the bone's lines of stress?

Answer 298

Trabeculae

Question 299

Which of the following is a function of yellow bone marrow? Storage of calcium Storage of energy Production of blood cells

Answer 299

Storage of energy

Question 300

What is the expanded end of a long bone to which tendons and ligaments attach called?

Answer 300

Epiphysis

Question 301

What are the two principle forms of ossification that occur in the development of the skeletal system?

Answer 301

Endochondral and intramembranous

Question 302

``` As a flat bone is produced by intramembranous ossification, which cells are responsible for the resorption of bone tissue that carves out the spongy bone's trabeculae? Chondrocytes Osteoclasts Chondroblasts Osteoblasts ```

Answer 302

Osteoclasts

Question 303

________ cartilage is the tissue which is replaced with bone during endochondral ossification

Answer 303

hyaline

Question 304

``` Where does the calcium and phosphate used to mineralize bone come from? The blood The lymph Osteoblasts Hyaline cartilage ```

Answer 304

The blood

Question 305

Fatty bone marrow that no longer produces blood cells is called ______ bone marrow

Answer 305

Yellow

Question 306

If a patient has abnormally high blood calcium levels, they are said to have a condition called ______.

Answer 306

hypercalcemia

Question 307

Which of the following best describes osteomalacia? An insufficient vitamin E intake in children The softening of the bones in adults due to calcium depletion A decreased osteoblast proliferation in adults The hardening of the bones in adults due to excess mineral deposits

Answer 307

The softening of the bones in adults due to calcium depletion

Question 308

Where does bone formation occur during endochondral ossification? Adipose tissue Hyaline cartilage model Fibrous membranous sheet

Answer 308

Hyaline cartilage model

Question 309

``` Vitamin D, also known as ______, raises the blood calcium level. cholesterol calcium calcitriol cholecalciferol ```

Answer 309

calcitriol

Question 310

``` Mineral deposition into bones begin when? In fetal ossification During puberty In the first month of life In the first year of life ```

Answer 310

In fetal ossification

Question 311

``` Which adult condition involves the softening of bones due to demineralization? Osteosarcoma Osteomalacia Rickets Osteomyelitis ```

Answer 311

Osteomalacia

Question 312

Which hormone inhibits osteoclasts and stimulates osteoblasts to lower blood calcium levels? Calcitonin Parathyroid hormone Calcitriol

Answer 312

Calcitonin

Question 313

``` Calcitriol acts on which organs to raise blood calcium levels? ((Multiple select question)) Bones Kidneys Brain Muscles Small intestines ```

Answer 313

Bones Kidneys Small intestines

Question 314

Which two ions are deposited by osteoblasts into the bone matrix?

Answer 314

Phosphate and calcium

Question 315

A low blood calcium level stimulates the release of which hormone? Parathyroid hormone Thyroid releasing hormone Calcitonin

Answer 315

Parathyroid hormone

Question 316

What does the hormone calcitonin do? Stimulates osteoclasts and inhibits osteoblasts Inhibits osteoclasts and stimulates osteoblasts Stimulates osteoclasts and stimulates osteoblasts Inhibits osteoclasts and inhibits osteoblasts

Answer 316

Inhibits osteoclasts and stimulates osteoblasts

Question 317

``` During fracture healing, cartilage is deposited in granulation tissue to form which of the following? A fracture hematoma A woven bone A hard callus A soft callus ```

Answer 317

A soft callus

Question 318

True or false: Most fractures are treated using closed reduction.

Answer 318

True

Question 319

``` PTH is a hormone released by parathyroid glands in response to which of the following? Sympathetic innervation Low blood calcium levels High blood potassium levels High blood iron levels ```

Answer 319

Low blood calcium levels

Question 320

A degenerative bone disease characterized by a loss of bone mass and an increased risk of fracture is called ______

Answer 320

osteoporosis

Question 321

Which condition occurs because of a defect in collagen deposition that causes bones to be exceptionally brittle?

Answer 321

Osteogenesis imperfecta

Question 322

Which hormone inhibits osteoclasts and stimulates osteoblasts to lower blood calcium levels? Calcitriol Parathyroid hormone Calcitonin

Answer 322

Calcitonin

Question 323

A hard callus is composed of _______

Answer 323

bone

Question 324

When surgery is needed to set a fracture, this treatment is called a(n) _____ reduction

Answer 324

open

Question 325

``` What often causes the loss of bone mass seen in osteoporosis in older women? A loss of androgen A loss of parathyroid hormone A loss of calcitriol A loss of estrogen ```

Answer 325

A loss of estrogen

Question 326

What is osteogenesis imperfecta? A loss of bone mineralization resulting in frequent fractures A defect in collagen deposition that renders bones exceptionally brittle An inflammation of osseous tissue due to bacterial infection

Answer 326

A defect in collagen deposition that renders bones exceptionally brittle

Question 327

Name all of the regions in the abdomen (9 regions)

Answer 327

Top row: hypochondriac, epigastric, left hypochondriac. Middle row: right lumbar, umbilical, left lumbar. Bottom row: right inguinal, hypogastric, left inguinal.

Question 328

Name the 4 quadrants of the abdomen

Answer 328

Right upper (RUQ), left upper (LUQ), right lower (RLQ), left lower (LLQ)

Question 329

Frontal region

Answer 329

Forehead

Question 330

Orbital region

Answer 330

Eyes

Question 331

Otic region

Answer 331

Ears

Question 332

Buccal region

Answer 332

Cheeks

Question 333

Mental region

Answer 333

Chin

Question 334

Oral region

Answer 334

Mouth

Question 335

Nasal region

Answer 335

Nose

Question 336

Cephalic region

Answer 336

Head

Question 337

Cervical region

Answer 337

Neck

Question 338

Acromial region

Answer 338

Shoulder

Question 339

Axillary region

Answer 339

Armpit

Question 340

Sternal region

Answer 340

Sternum

Question 341

Pectoral region

Answer 341

Pecs/ breast area

Question 342

Brachial region

Answer 342

Upper arm

Question 343

Cubital region

Answer 343

Inner elbow

Question 344

Anticubital reigon

Answer 344

Outer elbow

Question 345

Abdominal region

Answer 345

Overall front of abdomen

Question 346

Umbilical region

Answer 346

Bellybutton

Question 347

Inguinal region

Answer 347

Where your ovaries are

Question 348

Coxal area

Answer 348

Hips

Question 349

Antibrachial region

Answer 349

Forearm

Question 350

Carpal region

Answer 350

Wrist

Question 351

Palmar region

Answer 351

Palm

Question 352

Digital region

Answer 352

Fingers or toes

Question 353

Manus region

Answer 353

Hand

Question 354

Pubic region

Answer 354

Where your pubic bone is

Question 355

Femoral region

Answer 355

Femur

Question 356

Patellar region

Answer 356

Knee

Question 357

Crural region

Answer 357

Calves/ lower leg

Question 358

Tarsal region

Answer 358

Ankle region

Question 359

Metatarsal region

Answer 359

Long bones of toes

Question 360

Hallux region

Answer 360

Big toe

Question 361

Pollex region

Answer 361

Thumb

Question 362

Pedal region

Answer 362

Feet

Question 363

Occipital region

Answer 363

Back of head

Question 364

Vertebral region

Answer 364

Spinal column area

Question 365

Scapular region

Answer 365

Upper left and right back (scapulas)

Question 366

Infrascapular region

Answer 366

Middle left and right back

Question 367

Lumbar region

Answer 367

Lower back around the vertebral region

Question 368

Gluteal region

Answer 368

Butt

Question 369

Popliteal region

Answer 369

Back of knee

Question 370

Calcineal region

Answer 370

Heel of foot

Question 371

Plantar region

Answer 371

Arch of the foot

Question 372

Olecranial region

Answer 372

Back of elbow

Question 373

Define anterior-posterior

Answer 373

Front-back

Question 374

Define ventral-dorsal

Answer 374

Belly-back

Question 375

Define superior-inferior

Answer 375

Above and below (applies to axial skeleton)

Question 376

Define medial-intermediate-lateral

Answer 376

Toward the midline of the body, in-between, and away from the midline of the body

Question 377

Define ipsilateral-contralateral

Answer 377

Same side of body and opposite side of body

Question 378

Define proximal-middle-distal

Answer 378

Nearer to the top of the limb, away from the top of the limb

Question 379

Define superficial-deep

Answer 379

Closer to the body's surface and away from the body's surface

Question 380

Define the sagittal plane

Answer 380

Median plane; cuts the person in half vertically and separates left from right

Question 381

Define the transverse plane

Answer 381

Horizontal plane; cuts the person in half horizontally at the abdomen

Question 382

Define the coronal plane

Answer 382

Frontal plane; cuts the person in half vertically; separates front and back

Question 383

Define oblique plane

Answer 383

Diagonal plane; cuts the person in half diagonally from right acromial to left femoral

Question 384

Define pericardial cavity

Answer 384

Heart

Question 385

Define pelvic cavity

Answer 385

Cavity below the abdominal cavity

Question 386

Abdominopelvic cavity

Answer 386

Contains both the abdominal cavity and the pelvic cavity

Question 387

What divides the pericardial cavity and the thoracic cavity from the abdominal cavity?

Answer 387

The diaphragm

Question 388

Define the ventral cavity

Answer 388

Contains all cavities in the torso

Question 389

Define dorsal cavity

Answer 389

The cranial cavity and the vertebral cavity

Question 390

Define thoracic cavity

Answer 390

Contains the pleural cavity, pericardial cavity, and mediastinum

Question 391

Define the pleural cavity

Answer 391

Lung cavity

Question 392

There are ____ trillion cells of ____ different cell types

Answer 392

There are 50 trillion cells of 200 different cell types

Question 393

Name the 4 broad categories of tissues

Answer 393

Epithelial tissue Connective tissue Nervous tissue Muscular tissue

Question 394

Define histology

Answer 394

The study of tissues

Question 395

Define organ

Answer 395

A structure with discrete boundaries that is composed of two or more tissue types

Question 396

Define tissue

Answer 396

A group of similar cells and cell products working together to perform a specific role in an organ

Question 397

The four primary tissues differ from each other in what three ways?

Answer 397

- Types and functions of their cells - Characteristics of the matrix (extracellular material) - Relative amount of space occupied by cells versus matrix

Question 398

The extracellular matrix is composed of what two things?

Answer 398

1) Fibrous proteins | 2) Ground substance (clear gel)

Question 399

What other names can be used for 'ground substance'?

Answer 399

Tissue fluid, extracellular fluid (ECF), or interstitial fluid

Question 400

What are the six functions of epithelial tissue?

Answer 400

Covers body surfaces and lines body cavities Protect deeper tissues from injury and infection Produce and release chemical secretions Excretion and absorption Selectively filter substances Makes up most glands

Question 401

Describe the characteristics of epithelial tissue

Answer 401

``` Cells are very close together High rate of mitosis (regenerative) Apical and basal surfaces Basal surfaces faces basement membrane Apical surfaces may have microvilli or cilia Avascular but innervated ```

Question 402

The ______ _______ anchors the epithelium to the connective tissue below it

Answer 402

basement membrane

Question 403

Describe the differences between simple and stratified epithelium

Answer 403

``` Simple epithelia: -Contain one layer of cells -Named by shape of cells -All cells touch basement membrane Stratified epithelia: -Contain more than one layer -Named by shape of apical cells -Some cells rest on top of others and do not touch basement membrane ```

Question 404

In _____ epithelia, not all cells touch the basement membrane

Answer 404

stratified

Question 405

In ______ epithelia, all cells touch the basement membrane

Answer 405

simple

Question 406

What are the four types of simple epithelia?

Answer 406

Simple squamous Simple cuboidal Simple columnar Pseudostratified columnar

Question 407

Describe pseudostratified columnar cells

Answer 407

Every cell reaches the basement membrane but not all cells reach the free surface; Falsely appears stratified

Question 408

What are goblet cells?

Answer 408

Wineglass-shaped mucus-secreting cells in simple columnar and pseudostratified epithelia

Question 409

Describe simple squamous epithelium and where it can be found

Answer 409

- Permits rapid diffusion or transport of substances - Secretes serous fluid - Locations: air sacs of lungs (alveoli), inner lining of blood vessels & heart (endothelium), and serosa

Question 410

Describe simple cuboidal epithelium and where it can be found

Answer 410

- Absorption and secretion, mucus production and movement | - Locations: Kidney tubules and certain glands (thyroid, mammary and salivary glands)

Question 411

Describe simple columnar epithelium and where it can be found

Answer 411

- Single row of tall, narrow cells; oval nuclei in basal half of cell - Absorption and secretion; secretion of mucus - Brush border of microvilli, ciliated in some organs, may possess goblet cells - Locations: lining of GI tract, uterus, and uterine tubes

Question 412

Describe pseudostratified epithelium and where it can be found

Answer 412

- Secretes and propels mucus - Has cilia and goblet cells - Looks multilayered, but all cells touch basement membrane - Nuclei at several layers - Locations: respiratory tract

Question 413

Describe stratified epithelia

Answer 413

- Range from 2 to 20 or more layers of cells - Some cells rest directly on others - Only the deepest layer attaches to basement membrane

Question 414

Describe the types of stratified epithelia

Answer 414

- Three stratified epithelia are named for the shapes of their apical surface cells - Includes stratified squamous (only one expected to recognize and know functions) - The fourth type is transitional epithelium

Question 415

What is the most widespread epithelium in the human body?

Answer 415

Stratified squamous epithelium

Question 416

Describe stratified squamous epithelia and its two types

Answer 416

-Deepest layers undergo continuous mitosis -Daughter cells push toward the surface and become flatter as they migrate upward -Top layer is exfoliated -Two kinds Keratinized—top layer is dead Non-keratinized—top layer not dead

Question 417

Describe keratinized stratified squamous epithelium and where it's located

Answer 417

Resists abrasion; retards water loss through skin; resists penetration by pathogenic organisms Locations: epidermis; palms and soles heavily keratinized

Question 418

Describe non-keratinized stratified squamous epithelium and where it's located

Answer 418

Resists abrasion and penetration of pathogens | Locations: tongue, oral mucosa, esophagus, and vagina

Question 419

Describe transitional epithelium and where it's located

Answer 419

``` Permits stretching (distension); surface cells change from round to flat when stretched Locations: ureter and urinary bladder ```

Question 420

Describe the functions of connective tissue

Answer 420

``` Binding and Support Physical protection Immune protection Movement Storage Transport ```

Question 421

_____ tissue is the most diverse and abundant type of tissue

Answer 421

Connective

Question 422

Give examples of each of the functions of connective tissues

Answer 422

Connecting organs—tendons and ligaments Support—bones and cartilage Physical protection—cranium, ribs, sternum Immune protection—white blood cells attack foreign invaders Movement—bones provide lever system Storage—fat, calcium, phosphorus Heat production—metabolism of brown fat in infants Transport—blood

Question 423

Describe the characteristics of connective tissue

Answer 423

-Cells occupy less space than matrix (usually a large amount of extracellular matrix) -Most cells are not in direct contact with each other -Highly variable vascularity Loose connective tissues have many blood vessels, whereas cartilage has few or no blood vessels

Question 424

List and describe the 5 basic categories of connective tissue

Answer 424

- Fibrous Connective Tissue (Connective Tissue Proper): most diverse category; fibroblasts produce fibers and ground substance of matrix. - Adipose Tissue: may be classified with loose connective tissue proper - Cartilage (has 3 types): chondroblasts form matrix - Bone (Osseous tissue): osteoblasts form matrix - Blood

Question 425

List and describe the three types of fibers that can be found in fibrous connective tissue

Answer 425

- Collagen fibers: tough, flexible, and stretch-resisant - Reticular fibers: branching collagen fibers that forms a network - Elastic fibers (Elastin): Allows stretch and recoil

Question 426

What is fibrous connective tissue made of?

Answer 426

Fibers and a ground substance

Question 427

Describe the ground substance of fibrous connective tissues

Answer 427

Usually has a gelatinous to rubbery consistency

Question 428

Describe collagen fibers and where they're found

Answer 428

Found in fibrous connective tissue, it is the most abundant protein: 25%. Tendons, ligaments, and deep layer of the skin are mostly collagen.

Question 429

What is the most abundant proteines

Answer 429

Collagen (25%)

Question 430

Describe reticular fibers and where they can be found

Answer 430

Found in fibrous connective tissue, it is thin collagen fibers coated with glycoprotein. Forms the framework of the spleen and lymph nodes.

Question 431

Describe elastic fibers

Answer 431

Found in fibrous connective tissues, they branch and rejoin each other

Question 432

What are the two main types of fibrous connective tissue? Describe them.

Answer 432

Loose connective tissue and dense connective tissue. Loose connective tissue has more gel-like ground substance between cells, and its two types are areolar and reticular. Dense connective tissue has fibers that fill spaces between cells, and its two types are dense regular and dense irregular.

Question 433

What are the two main types of fibrous loose connective tissue?

Answer 433

Areolar and reticular

Question 434

What are the two main types of fibrous dense connective tissue?

Answer 434

Dense regular and dense irregular

Question 435

Describe areolar tissue (a type of fibrous loose connective tissue) and where it's found

Answer 435

All 3 fibers are found; loosely organized; abundant blood vessels. Wraps & cushions organs; underlies epithelia, in serous membranes, between muscles, passageways for nerves and blood vessels. Areolar tissue—loosely organized fibers, abundant blood vessels, and a lot of seemingly empty space Possess all six cell types Fibers run in random directions Mostly collagenous, but elastic and reticular also present Found in tissue sections from almost every part of the body Surrounds blood vessels and nerves Nearly every epithelium rests on a layer of areolar tissue Blood vessels provide nutrition to epithelium and waste removal Ready supply of infection-fighting leukocytes that move about freely in areolar tissue

Question 436

Describe reticular tissue (a type of fibrous loose connective tissue) and where it's found

Answer 436

Mesh of reticular fibers and fibroblasts Forms supportive framework for lymphatic organs Found in lymph nodes, spleen, thymus, and bone marrow

Question 437

Describe dense regular connective tissue (a type of fibrous dense connective tissue) and where it's found

Answer 437

Densely packed, parallel collagen fibers | Tendons attach muscles to bones and ligaments hold bones together

Question 438

Describe dense irregular connective tissue (a type of fibrous dense connective tissue) and where it's found

Answer 438

Dense, randomly arranged, collagen fibers Withstands unpredictable stresses Locations: dermis of skin; organ capsules

Question 439

Describe adipose tissue

Answer 439

Space between adipocytes occupied by areolar tissue, reticular tissue, and blood capillaries Functions: Energy storage, insulation, cushioning Fat is the body’s primary energy reservoir The quantity of stored triglyceride and the number of adipocytes are quite stable in a person Fat is recycled continuously New triglyceride synthesized while old molecules hydrolyzed and released to blood

Question 440

Describe cartilage

Answer 440

Stiff connective tissue with flexible matrix

Question 441

Describe what chondroblasts do

Answer 441

They produce the matrix that will trap them

Question 442

Describe chondrocytes

Answer 442

Cartilage cells that are trapped in lacunae (cavities)

Question 443

Describe perichondrium

Answer 443

A sheath of dense irregular connective tissue that surrounds elastic and most hyaline cartilage (not articular cartilage); contains reserve population of chondroblasts

Question 444

Describe the characteristics of cartilage

Answer 444

-No blood vessels, which means that diffusion brings nutrients and removes wastes and it heals slowly. -Matrix contains collagen fibers -Types of cartilage vary with fiber composition (Hyaline cartilage, fibrocartilage, and elastic cartilage)

Question 445

List the 3 types of cartilage

Answer 445

Hyaline cartilage, fibrocartilage, and elastic cartilage

Question 446

Describe hyaline cartilage and where it's found

Answer 446

Clear, glassy appearance because of fineness of collagen fibers Locations: articular cartilage, costal cartilage, respiratory cartilage, fetal skeleton

Question 447

Describe elastic cartilage and where it's found

Answer 447

Contains abundant elastic fibers; covered with perichondrium Provides flexible, elastic support Locations: external ear and epiglottis

Question 448

Describe fibrocartilage and where it's found

Answer 448

Contains large bundles of collagen fibers Resists compression and absorbs shock Locations: pubic symphysis, menisci of knee, and intervertebral discs

Question 449

Describe bone

Answer 449

Bone (osseous) tissue has a hard calcified matrix with collagen fibers

Question 450

Define osteoblasts and osteocytes

Answer 450

Osteoblasts produce the matrix | Osteocytes are mature bone cells within lacunae

Question 451

What are the two types of bone?

Answer 451

Spongy bone: porous appearance | Compact bone: denser, calcified tissue with no visible spaces

Question 452

Describe compact bone

Answer 452

Compact bone is arranged in cylinders that surround central canals that run longitudinally through shafts of long bones

Question 453

What type of tissue is blood, and what does it do?

Answer 453

Fluid connective tissue that transports cells and dissolved matter from place to place

Question 454

Describe what blood is made of

Answer 454

``` Plasma (blood’s ground substance) and formed elements (cells and cell fragments) ```

Question 455

List and describe the formed elements of blood

Answer 455

Erythrocytes—red blood cells (RBCs) Leukocytes—white blood cells (WBCs) Platelets—cell fragments involved in clotting

Question 456

What are the two types of excitable tissues?

Answer 456

Muscle and nervous

Question 457

Define excitability

Answer 457

The ability to respond to stimuli by changing membrane potential

Question 458

Define membrane potential

Answer 458

An electrical charge difference (voltage) that occurs across the cell membrane

Question 459

Describe what happens when changes in voltage happen in muscle and nerve cells

Answer 459

In nerve cells: changes in voltage result in rapid transmission of signals to other cells In muscle cells: changes in voltage result in contraction, shortening of the cell

Question 460

Define nervous tissue

Answer 460

A tissue specialized for communication by electrical and chemical signals

Question 461

What are the two components of nervous tissue?

Answer 461

Neurons (nerve cells) and neuroglia (glial cells)

Question 462

Describe neurons

Answer 462

Detect stimuli Respond quickly Transmit information rapidly to other cells Cannot replicate/ divide

Question 463

Describe neuroglia

Answer 463

Protect and assist neurons “Housekeepers” of nervous system More numerous than neurons Can replicate/ divide

Question 464

What are the three parts of a neuron?

Answer 464

Axon, dendrites, and neurosoma

Question 465

Describe muscular tissue and its functions

Answer 465

- Elongated cells that are specialized to contract (shorten) in response to stimulation - Primary job is to exert physical force on other tissues and organs - Creates movements involved in body and limb movement, digestion, waste elimination, breathing, speech, and blood circulation - Important source of body heat

Question 466

List the 3 types of muscle

Answer 466

Skeletal, cardiac, and smooth

Question 467

Describe skeletal muscle tissue

Answer 467

Long thin cells called muscle fibers; multinucleate Most skeletal muscles attach to bone Striations—alternating dark and light bands Voluntary—conscious control over skeletal muscles

Question 468

Describe cardiac muscle tissue

Answer 468

Cardiomyocytes are branched, shorter than skeletal muscle fibers; uninucleate Intercalated discs join cardiomyocytes end to end Provide electrical and mechanical connection Striated and involuntary (not under conscious control)

Question 469

Describe smooth muscle tissue

Answer 469

Short, fusiform myocytes; uninucleate Non-striated and involuntary Most is visceral muscle—making up parts of walls of hollow organs

Question 470

Describe the 3 parts of the neuron

Answer 470

``` Neurosoma (cell body) -Contains nucleus & other organelles -Controls protein synthesis Dendrites -Multiple short, branched processes -Receive signals from other cells -Transmit messages to neurosoma Axon (nerve fiber) -Sends outgoing signals to other cells -Can be more than a meter long ```

Question 471

Define cell junctions

Answer 471

Connections between two cells

Question 472

Most cells are anchored to what?

Answer 472

Each other or the matrix

Question 473

Describe the purpose of cell junctions

Answer 473

Cells communicate with each other, resist mechanical stress, and control what moves through the gaps between them

Question 474

What are the 3 types of cell junctions?

Answer 474

Tight junctions, desmosomes, and gap junctions

Question 475

Describe tight junctions and where they're found

Answer 475

- Seals off intercellular space, making it difficult for substance to pass between cells - Found in the epidermis, stomach, and small intestines

Question 476

Describe desmosomes and where they're found

Answer 476

- A type of cell junction that keeps cells from pulling apart—resist mechanical stress. - Found in cardiac muscle, the uterine cervix, and the epidermis

Question 477

Describe gap (communication) junctions and where they're found

Answer 477

- Formed by ring-like connexons; the cells now share part of their cell membrane. - Ions, nutrients, and other small solutes pass between cells - Found in cardiac and smooth muscle, embryonic tissue, lens and cornea

Question 478

True or false: gap junctions are absent in skeletal muscle

Answer 478

True

Question 479

Define and describe glands

Answer 479

- A cell or organ that secretes substances for use elsewhere in the body or releases them for elimination from the body - Usually composed of epithelial tissue with a connective tissue framework and capsule

Question 480

Describe the differences between secretion and excretion

Answer 480

Secretion—product useful to the body | Excretion—waste product

Question 481

Describe exocrine glands

Answer 481

- Maintain their contact with surface of epithelium by way of a duct - Surfaces can be external (examples: sweat, tear glands) or internal (examples: pancreas, salivary glands)

Question 482

Describe endocrine glands

Answer 482

-They have no ducts; instead, they secrete hormones directly into blood

Question 483

Give some examples of organs that have both endocrine and exocrine responsibilities

Answer 483

The liver, gonads, and pancreas

Question 484

Define hormones

Answer 484

Chemical messengers that stimulate cells elsewhere in the body

Question 485

Give examples of endocrine glands

Answer 485

Thyroid, adrenal, and pituitary glands

Question 486

Describe unicelluar glands and give examples

Answer 486

- Found in an epithelium that is predominantly nonsecretory - Can be exocrine or endocrine - Examples: mucus-secreting goblet cells in trachea or endocrine cells of stomach

Question 487

What are the different characteristics we can use to describe exocrine glands?

Answer 487

Duct shape: simple (unbranched) vs. compound (branched) Gland shape: Tubular: narrow secretory portion Acinar: secretory cells form dilated sac (acinus or alveolus) Tubuloacinar: both tubular and acinar portions

Question 488

Describe the 3 different modes of secretion

Answer 488

1) Merocrine - Uses vesicles that release their secretion by exocytosis. - Used by eccrine glands. 2) Apocrine - Lipid droplet covered by membrane and cytoplasm buds from cell surface - Mode of milk fat secretion by mammary gland cells 3) Holocrine: - Cells accumulate a product until they disintegrate - Secrete a mixture of cell fragments and synthesized substances - Ex: sebaceous glands of hair and skin, eyelid glands.

Question 489

Describe the merocrine mode of secretion

Answer 489

- Uses vesicles that release their secretion by exocytosis. | - Used by eccrine glands.

Question 490

Describe the apocrine mode of secretion and give an example

Answer 490

- Lipid droplet covered by membrane and cytoplasm buds from cell surface - Mode of milk fat secretion by mammary gland cells

Question 491

Describe the holocrine mode of secretion and give examples

Answer 491

- Cells accumulate a product until they disintegrate - Secrete a mixture of cell fragments and synthesized substances - Ex: sebaceous glands of hair and skin, eyelid glands.

Question 492

True or false: Membranes may be only epithelial, only connective, or a mix of epithelial, connective, and muscular tissues

Answer 492

True

Question 493

What is the largest membrane in the body?

Answer 493

Cutaneous membrane (the skin)

Question 494

Define and describe the cutaneous membrane

Answer 494

- Cutaneous membrane (the skin) is the largest membrane in the body. - Composed of stratified squamous epithelium (epidermis) resting on a layer of connective tissue (dermis) - Relatively dry layer serves protective function

Question 495

What are the two main types of internal membrane?

Answer 495

Mucous membranes and serous membranes.

Question 496

Describe mucous membranes (mucosa)

Answer 496

- Layers consists of epithelium, areolar tissue (lamina propria), and smooth muscle (muscularis mucosa) - Lines cavities/passages that open to the external environment - Produces mucus (thicker, stickier)

Question 497

What 4 organ systems have mucous membranes?

Answer 497

Reproductive, digestive, respiratory, and urinary

Question 498

Describe serous membranes (serosa)

Answer 498

- Composed of simple squamous epithelium resting on a layer of areolar tissue - Internal membrane; lines cavities with no connection to the outside - Produces serous fluid

Question 499

What are some membranes made up of only epithelium?

Answer 499

Anterior surfaces of cornea and lens of eye

Question 500

What are 4 membranes made up of only connective tissues?

Answer 500

Dura mater (meninges) Synovial membranes Periosteum Perichondrium

Question 501

Define tissue growth

Answer 501

Increasing the number of cells or size of existing cells

Question 502

Define hyperplasia

Answer 502

Growth through cell multiplication

Question 503

Define hypertrophy and give two examples

Answer 503

The enlargement of preexisting cells | Examples: Muscle growth through exercise, accumulation of body fat

Question 504

Define and describe neoplasia

Answer 504

The development of a tumor (neoplasm) | -It can be benign or malignant, and is composed of abnormal, nonfunctional tissue

Question 505

What are the 3 types of tissue growth?

Answer 505

Hypertrophy, hyperplasia, and neoplasia

Question 506

Define, describe, and give examples of the two modes of tissue repair

Answer 506

1) Regeneration: replacement of dead or damaged cells by the same type of cell as before - Restores normal function - Examples: repair of minor skin or liver injuries 2) Fibrosis: replacement of damaged cells with scar tissue - Scar holds organs together, but does not restore function - Examples: repair of severe cuts and burns, scarring of lungs in tuberculosis

Question 507

List the steps of healing a skin wound

Answer 507

1) Inflammation: brings white blood cells, platelets, etc to the area. Creates swollenness, warmth, and redness. 2)Initial patch up and cleaning: Blood clot forms; forms scab that temporarily seals the wound and blocks infection. Macrophages clean up the scene. 3) New capillaries sprout from nearby vessels. Fibroblasts deposit new collagen Begins 3-4 days after the injury and lasts up to 2 weeks. 4) Regeneration, fibrosis, and remodeling: epithelial cells around the wound multiply and migrate beneath the scab (tissue regenerates) Fibrosis: Underlying connective tissue undergoes fibrosis Remodeling (maturation) phase begins several weeks after injury and may last up to 2 years

Question 508

Categorize body tissues by how well they repair themselves into groups of good, moderate, poor, and almost no repair

Answer 508

Good: epithelial, bone, blood, areolar, dense irregular Moderate: dense regular, smooth muscle Poor: cartilage, skeletal muscle Almost none: cardiac muscle, neurons (in CNS)

Question 509

Name the four primary classes into which all adult tissues are classified.

Answer 509

Epithelial tissue, connective tissue, nervous tissue, and muscular tissue

Question 510

Define histology

Answer 510

The study of tissues

Question 511

Compare the general features of the four major tissue types.

Answer 511

All 4 tissues types are similar to each other in the following ways: All tissue types are made up of cells. All tissue types have an extracellular matrix All cells and tissues occupy space

Question 512

Contrast the general features of the four major tissue types.

Answer 512

The 4 tissue types vary in: The types and functions of their cells The characteristics of their matrix (extracellular material) The relative amount of space occupied by their cells versus their matrix

Question 513

Describe the unique functions of the epithelium

Answer 513

- It covers body surfaces and lines body cavities - It protects deeper tissues from injury and infection - It produces and releases chemical secretions; also involved with excretion and absorption - It selectively filters substances - It makes up most glands

Question 514

Describe the unique characteristics of epithelium

Answer 514

- Its cells are very close together - Its cells have a high rate of mitosis (regenerative) - Has apical and basal surfaces

Question 515

Name and describe the 3 types of simple epithelium

Answer 515

1) Simple squamous Permits rapid diffusion or transport of substances It secretes serous fluid Found in: air sacs of lungs (alveoli), inner lining of blood vessels & heart (endothelium), and serosa 2) Simple cuboidal It’s good at absorption and secretion, mucus production, and movement Found in: Kidney tubules and certain glands (thyroid, mammary and salivary glands) 3) Simple columnar Specializes in absorption and secretion; secretion of mucus Has a brush border of microvilli, ciliated in some organs, and may possess goblet cells. It’s the only tissue with microvilli. Made up of a single row of tall, narrow cells; oval nuclei in basal half of cell Found in: the lining of the GI tract, the uterus, and uterine tubes 4) Pseudostratified columnar Secretes and propels mucus Has cilia and goblet cells Looks multilayered, but all cells touch the basement membrane Has nuclei at several layers Found in the respiratory tract

Question 516

Describe stratified squamous epithelium

Answer 516

The most widespread epithelium in the body Deepest layers undergo continuous mitosis Daughter cells push toward the surface and become flatter as they migrate upward, and the top layer is exfoliated

Question 517

Name and describe the two types of stratified squamous epithelium

Answer 517

1) Keratinized stratified squamous epithelia Resists abrasion; retards water loss through skin; resists penetration by pathogenic organisms. Top layer of cells are dead. Locations: epidermis; palms and soles heavily keratinized 2) Non-Keratinized stratified squamous epithelia Resists abrasion and penetration of pathogens Top layer of cells is not dead. Locations: tongue, oral mucosa, esophagus, and vagina

Question 518

Name the two main types of stratified epithelia. Can these be broken down into more types?

Answer 518

Stratified squamous epithelia and transitional epithelia. There are two types of stratified squamous epithelia: keratinized and non-keratinized.

Question 519

Describe transitional epithelia and where it's located

Answer 519

A type of stratified epithelia that permits stretching (distension); surface cells change from round to flat when stretched Locations: ureter and urinary bladder

Question 520

Explain how the structural differences between epithelia relate to their functional differences.

Answer 520

1) Microvilli are only found in simple columnar epithelial tissue, and since microvilli increase surface area of a cell exponentially, this allows simple columnar epithelium to be excellent at absorption and secretion (since increased cell surface area equals increased absorption rate). The microvilli and celiation in some organs (such as in the uterine tubes) allows for cells such as eggs to be moved around. 2) Simple squamous epithelia has a lot of empty space, which is how it permits rapid diffusion and transportation of substances, and is why it’s found in the alveoli of the lungs (since they need to absorb oxygen). 3) Simple cuboidal epithelium are able to absorb and secrete easily because they appear flattened, so there is less surface area substances need to pass through. 4) Transitional epithelium’s top layer of cells (surface cells) are able to change from round to flat when stretched out, which makes them perfect for areas that need to stretch such as the urinary bladder (which needs to stretch to hold urine).

Question 521

Describe the properties that most connective tissues have in common.

Answer 521

-Their cells occupy less space than matrix (usually there’s a large amount of extracellular matrix) -Most of their cells are not in direct contact with each other -They have a highly variable vascularity (Loose connective tissues have many blood vessels whereas cartilage has few or no blood vessels)

Question 522

What is the most diverse and abundant type of tissue

Answer 522

Connective tissue

Question 523

Discuss the types of cells found in connective tissue.

Answer 523

1) Fibrous Connective Tissue (Connective Tissue Proper) Made up of fibers (collagen, reticular, and elastic fibers) and ground substance of the matrix produced by fibroblasts. 2) Adipose Tissue Adipocytes (fat cells) contain a large amount of space reserved for storing fats. 3) Cartilage Chondroblasts form the matrix, which is then occupied by chondrocytes (cartilage cells) 4) Bone (Osseous tissue) Osteoblasts form the matrix, which is then occupied by osteocytes. 5) Blood Made up of plasma, platelets, WBCs, and RBCs.

Question 524

What are the two main types of fibrous connective tissue? Can they be broken down into further categories.

Answer 524

Loose and dense connective tissue are the two main types. The two types of loose fibrous connective tissue are areolar and reticular. The two types of dense connective tissue are dense regular and dense irregular

Question 525

Define and describe areolar tissue. Also, where is it found?

Answer 525

- One of the two types of loose connective tissue, which is a type of fibrous connective tissue. - All 3 fibers/ 6 total cell types are found; loosely organized; abundant blood vessels; lots of empty space. - Mostly collagenous, but elastic and reticular also present - Wraps & cushions organs; underlies epithelia, in serous membranes, between muscles, passageways for nerves and blood vessels - Fibers run in random directions - Found in tissue sections from almost every part of the body - Surrounds blood vessels and nerves - Nearly every epithelium rests on a layer of areolar tissue - Blood vessels provide nutrition to epithelium and waste removal - Ready supply of infection-fighting leukocytes that move about freely in areolar tissue

Question 526

Define and describe reticular tissue. Also, where is it found?

Answer 526

- One of the two types of loose connective tissue, which is a type of fibrous connective tissue. - Mesh of reticular fibers and fibroblasts - Forms supportive framework for lymphatic organs - Found in lymph nodes, spleen, thymus, and bone marrow

Question 527

Define and describe dense regular tissue

Answer 527

- One of the two types of dense connective tissue, which is one of the types of fibrous connective tissue. - Densely packed, parallel collagen fibers - Tendons attach muscles to bones and ligaments hold bones together

Question 528

Define and describe dense irregular tissue

Answer 528

- Dense, randomly arranged, collagen fibers - Withstands unpredictable stresses - Locations: dermis of skin; organ capsules

Question 529

Describe adipose tissue

Answer 529

- A type of connective tissue - Space between adipocytes occupied by areolar tissue, reticular tissue, and blood capillaries. - The quantity of stored triglyceride and the number of adipocytes are quite stable in a person. - Fat is recycled continuously; new triglycerides synthesized while old molecules hydrolyzed and released to blood - Functions: Energy storage, insulation, cushioning - Fat is the body’s primary form of energy storage.

Question 530

Describe cartilage

Answer 530

Stiff connective tissue with flexible matrix; chondroblasts produce the matrix that will trap them in lacunae (cavities) and become chondrocytes. Contains reserve population of chondroblasts

Question 531

List and describe the 3 types of cartilage and where they can be found

Answer 531

1) Hyaline cartilage Clear, glassy appearance because of fineness of collagen fibers Surrounded by perichondrium Locations: articular cartilage, costal cartilage, respiratory cartilage, fetal skeleton 2) Elastic cartilage Contains abundant elastic fibers; covered with perichondrium Provides flexible, elastic support Locations: external ear and epiglottis 3) Fibrocartilage Contains large bundles of collagen fibers; no perichondrium. Resists compression and absorbs shock Locations: pubic symphysis, menisci of knee, and intervertebral discs

Question 532

Describe bone (osseous tissue)

Answer 532

Has a hard calcified matrix with collagen fibers; made by osteoblasts who build and become osteocytes in lacunae. A type of connective tissue

Question 533

Describe the two types of bone (osseous tissue)

Answer 533

1) Spongy bone Porous appearance with visible holes. 2) Compact bone Compact bone is arranged in cylinders that surround central canals that run longitudinally through shafts of long bones

Question 534

Describe blood

Answer 534

-A fluid connective tissue -Transports cells and dissolved matter from place to place -Plasma—blood’s ground substance Formed elements—cells and cell fragments: -Erythrocytes—red blood cells (RBCs) -Leukocytes—white blood cells (WBCs) -Platelets—cell fragments involved in clotting

Question 535

Explain what distinguishes excitable tissues from other tissues.

Answer 535

They have the ability to respond to stimuli by changing membrane potential.

Question 536

Name the cell types that compose nervous tissue.

Answer 536

Neurons and neuroglia.

Question 537

Identify and describe the major parts of a nerve cell.

Answer 537

``` 1) Neurosoma (cell body) Contains nucleus & other organelles Controls protein synthesis 2) Dendrites Multiple short, branched processes Receive signals from other cells Transmit messages to neurosoma 3) Axon (nerve fiber) Sends outgoing signals to other cells Can be more than a meter long ```

Question 538

Name the three kinds of muscular tissue and describe them

Answer 538

1) Skeletal: Long thin cells called muscle fibers; multinucleate Most skeletal muscles attach to bone Striations—alternating dark and light bands They only type of muscle that is voluntary, meaning conscious control over skeletal muscles. 2) Cardiac: Cardiomyocytes are branched, shorter than skeletal muscle fibers; uninucleate Intercalated discs join cardiomyocytes end to end Provide electrical and mechanical connection Striated and involuntary (not under conscious control) 3) Smooth: Short, fusiform myocytes; uninucleate Non-striated and involuntary Most is visceral muscle—making up parts of walls of hollow organs

Question 539

Define cell junctions and describe what they do

Answer 539

Cell junctions are connections between two cells; most cells are anchored to each other through a cell junction or their matrix Cells communicate with each other, resist mechanical stress, and control what moves through the gaps between them

Question 540

List and describe the 3 types of cell junctions

Answer 540

1) Tight junctions: Seals off intercellular space, making it difficult for substance to pass between cells Found in the epidermis, stomach, and small intestines 2) Desmosomes A type of cell junction that keeps cells from pulling apart—resist mechanical stress. Found in cardiac muscle, the uterine cervix, and the epidermis 3) Gap junctions Formed by ring-like connexons; the cells now share part of their cell membrane. Ions, nutrients, and other small solutes pass between cells Found in cardiac and smooth muscle, embryonic tissue, lens and cornea

Question 541

Describe the two main kinds of glands

Answer 541

1) Exocrine glands: maintain their contact with surface of epithelium by way of a duct Their surfaces can be external (examples: sweat, tear glands) or internal (examples: pancreas, salivary glands) Classified by duct shape and gland shape. 2) Endocrine glands: have no ducts; secrete hormones directly into blood Examples: thyroid, adrenal, and pituitary glands.

Question 542

Describe unicellular glands and give examples

Answer 542

Found in an epithelium that is predominantly nonsecretory; can be exocrine or endocrine Examples: mucus-secreting goblet cells in trachea or endocrine cells of stomach

Question 543

Define a gland and describe its typical anatomy

Answer 543

- A gland is defined as a cell or organ that secretes substances for use elsewhere in the body or releases them for elimination from the body - They are usually composed of epithelial tissue with a connective tissue framework and capsule

Question 544

Name and describe the three different modes of glandular secretion.

Answer 544

1) Merocrine Uses vesicles that release their secretion by exocytosis. Used by eccrine glands. 2) Apocrine Lipid droplet covered by membrane and cytoplasm buds from cell surface Mode of milk fat secretion by mammary gland cells 3) Holocrine Cells accumulate a product until they disintegrate (entire cell dies and is secreted, hence why these glands’ substances are oily) Secrete a mixture of cell fragments and synthesized substances Ex: sebaceous glands of hair and skin, eyelid glands.

Question 545

Describe the types and composition of the body’s membranes.

Answer 545

1) Cutaneous membrane (the skin) Largest membrane in the body Stratified squamous epithelium (epidermis) resting on a layer of connective tissue (dermis) Relatively dry layer serves protective function 2) Mucosal membranes Layers consists of epithelium, areolar tissue (lamina propria), and smooth muscle (muscularis mucosa) An internal membrane that lines cavities/passages that open to the external environment Produces mucus (thicker, stickier) This membrane can be found in 4 organ systems: reproductive, digestive, respiratory, and urinary. 3) Serous membranes Composed of simple squamous epithelium resting on a layer of areolar tissue Internal membrane; lines cavities with no connection to the outside Produces serous fluid 4) Membranes made of only epithelium: Anterior surfaces of cornea and lens of eye 5) Membranes made of only connective tissue: Dura mater (meninges), synovial membranes, periosteum, perichondrium

Question 546

Name and describe the modes of tissue growth.

Answer 546

1) Hyperplasia: growth through cell multiplication 2) Hypertrophy: enlargement of preexisting cells Examples: muscle growth through exercise, accumulation of body fat 3) Neoplasia: development of a tumor (neoplasm) Tumor can be benign or malignant Composed of abnormal, nonfunctional tissue

Question 547

Name and describe the ways the body repairs damaged tissues.

Answer 547

1) Regeneration: replacement of dead or damaged cells by the same type of cell as before Restores normal function Examples: repair of minor skin or liver injuries 2) Fibrosis: replacement of damaged cells with scar tissue Scar holds organs together, but does not restore function Examples: repair of severe cuts and burns, scarring of lungs in tuberculosis

Question 548

List the functions of the skin and relate them to its structure.

Answer 548

1) Resistance to trauma and infection: - Keratin - Dermacidin & defensins - Acid mantle acts as an antimicrobial barrier. - There are very few spaces between cells in the epidermis to protect against trauma and infection. 2) Other barrier functions - Water (protects against dehydration): The stratum corneum is a layer of dead cell membranes, which provides a layer of protection against water. - UV radiation: melanin aids in UV protection - Harmful chemicals 3) Vitamin D synthesis - Skin carries out first step; Liver & kidneys complete process 4) Sensation receptors - Touch, temperature, pressure, vibration, tickle, itch, and pain sensations 5) Regulation of body temperature - Thermoreceptors - Vasoconstriction/vasodilation; if you are too warm, cutaneous blood vessels vasodilate - Perspiration 6) Nonverbal communication - Facial expressions - The color of skin based on factors such as blood flow/ hemoglobin and carotene can display signs of illness without verbal communication.

Question 549

Describe the histological structure of the epidermis, dermis, and subcutaneous tissue.

Answer 549

1) The epidermis consists of keratinized stratified squamous epithelial tissue 2) The dermis consists of two layers: - Papillary layer: A thin layer of areolar connective tissue - Reticular layer: A thicker layer of dense irregular connective tissue. 3) Subcutaneous tissue: Consists primarily of adipose connective tissue, but also contains areolar connective tissue.

Question 550

Describe the difference between thick and thin skin.

Answer 550

Unlike thin skin, thick skin does not contain hair follicles and it has an extra thin white/clear epidermal layer that is not present in thin skin called the stratum lucidum. This causes dermal papillae to be more pronounced in thick skin.

Question 551

Describe the normal and pathological colors that the skin can have

Answer 551

1) Cyanosis: blueness due to oxygen deficiency - Oxygen deficiency is usually due to events that cause respiratory distress. This includes things such as drowning, severe asthma attacks, lung failure, pertussis in infants, choking, etc. 2) Erythema: redness due to increased blood flow to skin. - Increased blood flow to the skin can be caused by injuries such as heat burns, sunburns, consumption of alcohol, or strong emotions such as embarrassment or anger. 3) Pallor: paleness due to decreased blood flow to skin - Decreased blood to the skin often happens during or immediately prior to syncope or during illness. Malnutrition can also be a cause of pallor. 4) Albinism: milky white skin and blue-gray eyes due to genetic lack of melanin synthesizing enzyme - This is only due to genetic mutations and cannot develop during a person’s lifetime after birth. 5) Jaundice: yellowing due to bilirubin in blood (can be caused by compromised liver function) - Often seen in newborn babies or those with liver failure. 6) Hematoma: bruising (clotted blood under skin) - Usually happens due to blunt force to the skin

Question 552

Describe the basic structure of a hair and its accessory structures (piloerector muscle, etc.)

Answer 552

1) Bulb: Contains matrix cells (mitotically active cells). Located beneath the surface of the skin and is wider than the rest of the hair. 2) Root: the remainder of the hair in the follicle Located beneath the surface of the skin and is just above the bulb. 3) Shaft: the portion of the hair that’s above the skin surface 4) Three layers of a hair can be seen in a cross section: Medulla (core), Cortex, Cuticle (outer layer) 5) Hair receptors: Sensory nerve fibers that are entwined with follicles that detect hair movement 6) Piloerector muscle: Smooth muscle that attaches the follicle to dermis; contracts to make hair stand on its end, which causes goose bumps

Question 553

Discuss the basic functions of hair.

Answer 553

1) Protection: The hair on your scalp provides your head with more protection against sunburns. 2) Light touch: Hair helps you sense light touch due to the presence of hair receptors. 3) Heat retention: The hair on your head provides an extra layer to trap warm air. 4) Excretion: Sebaceous glands found on hair follicles excrete sebum, which helps keep skin and hair from drying out.

Question 554

Describe the basic structure and function of nails.

Answer 554

Nails are clear, hard derivatives of stratum corneum. They’re composed of thin, dead cells packed with hard keratin. Provides the tops of our fingertips and toes with an extra layer of protection.

Question 555

Name two types of sweat glands, and describe the structure and function of each

Answer 555

1) Merocrine sweat glands - Most numerous type of skin glands - The gland’s duct opens to the surface of the skin - Regulates body temperature by allowing for perspiration 2) Apocrine sweat glands - Found in the regions of the groin, anal region, axilla, areola, and beard (males) - These glands are inactive until puberty; responds to stress and sexual stimulation - Ducts lead to nearby hair follicles - Believed to secrete pheromones

Question 556

Describe the location, structure, and function of sebaceous glands.

Answer 556

Most sebaceous glands open into a hair follicle, meaning they aren’t present in thick skin. They utilize a holocrine secretion style and secrete sebum, which is an oily secretion that keeps skin and hair from becoming dry, brittle, and cracked. It also inhibits the growth of bacteria & fungi (ringworm)

Question 557

Name some other cutaneous glands

Answer 557

1 1) Ceruminous glands in external ear canal - Modified apocrine sweat glands - Forms earwax (cerumen) 2) Mammary Glands - Milk-producing modified apocrine sweat glands that develop only during pregnancy - Two rows of mammary glands can be found in most mammals

Question 558

Describe the three most common forms of skin cancer.

Answer 558

1) Basal cell carcinoma - Most common form of skin cancer, but the least malignant - Most often on the head, neck, and hands - Most common in fair-skinned people and the elderly - Forms from cells in stratum basale - Lesion is small, shiny bump with central depression and beaded edges 2) Squamous cell carcinoma - May metastasize if not removed; tends to metastasize to lymph nodes and may become lethal. However, the chance of recovery is good with early detection and surgical removal - Arises from keratinocytes of stratum spinosum - Lesions usually found on the scalp, ears, lower lip, or back of the hand - They typically have a raised, reddened, scaly appearance later forming a concave ulcer 3) Melanoma - Least common (less than 5% of skin cancers) but very malignant. Can be successfully removed if caught early, but if it metastasizes it is usually fatal - Skin cancer that arises from melanocytes - Greatest risk factor: familial history of malignant melanoma - Highest incidence in men, redheads, and people who had severe sunburn as a child

Question 559

Describe melanomas

Answer 559

Least common (less than 5% of skin cancers) but very malignant. Can be successfully removed if caught early, but if it metastasizes it is usually fatal Skin cancer that arises from melanocytes Greatest risk factor: familial history of malignant melanoma Highest incidence in men, redheads, and people who had severe sunburn as a child

Question 560

Describe basal cell carcinoma

Answer 560

Most common form of skin cancer, but the least malignant Most often on the head, neck, and hands Most common in fair-skinned people and the elderly Forms from cells in stratum basale Lesion is small, shiny bump with central depression and beaded edges

Question 561

Describe squamous cell carcinoma

Answer 561

May metastasize if not removed; tends to metastasize to lymph nodes and may become lethal. However, the chance of recovery is good with early detection and surgical removal Arises from keratinocytes of stratum spinosum Lesions usually found on the scalp, ears, lower lip, or back of the hand They typically have a raised, reddened, scaly appearance later forming a concave ulcer

Question 562

Describe the three classes of burns.

Answer 562

1) First-degree burn - Involves only the epidermis and heals in days. 2) Second-degree burn - A partial-thickness burn; involves part of dermis - May appear red, tan, or white; often blistered and painful - Takes two weeks to several months to heal and may leave scars 3) Third-degree burn - A full-thickness burn; involves epidermis, all of dermis, and often some deeper tissues - Often requires skin grafts - Typically requires fluid replacement, infection control, and supplemental nutrition

Question 563

Name the tissues and organs that compose the skeletal system.

Answer 563

Major organs: Bones. Major tissues: Bones are made up of bone tissue, bone marrow, cartilage, adipose tissue, nervous tissue, and fibrous connective tissue

Question 564

Describe the major functions of the skeletal system and give examples

Answer 564

1) Support: Limb bones and vertebrae support the body; jaw bone supports the teeth; bones support viscera 2) Protection: Cranial bones protect the brain, vertebrae protect the spinal cord, ribs protect the heart and lungs, etc 3) Movement: Allows for movement of limbs and breathing (requires action of muscles on bones). 4) Electrolyte balance: Helps regulate calcium & phosphate levels 5) Acid–base balance: Buffers the blood against large pH changes by altering phosphate and carbonate salt levels 6) Blood formation: Red bone marrow produces red blood cells.

Question 565

Distinguish between bones as a tissue and as an organ.

Answer 565

Bones (organs) have multiple types of tissue; each individual bone in your body is a separate organ. One of the types of tissue found in bones (organs) is called bone tissue, also called osseous tissue.

Question 566

Describe the types of bones classified by shape and give examples

Answer 566

1) Flat bones: cranial bones, sternum, ribs, scapula, hip. - These bones are usually for protection 2) Long bones: femur, humerus, radius and ulna, metatarsals, metacarpals, digits of manus and pedal regions, etc - These bones are usually in appendages, for movement 3) Short bones: carpal (wrist) bones, tarsal (ankle) bones 4) Irregular bones: vertebrae, some skull bones (inner ear bones) 5) Sesamoid (type of short bone): patella - Sesamoid bones develop in a tendon (or ligament) in response to a need for more leverage. 6) Sutural (wormian) bones - Sutural bones are the extra bones in the sutures (especially the lambdoid suture) of the skull. - Everyone has a different number of sutures in their cranium (i.e. some people only have 1, while others may have 4, depending on how their cranium formed).

Question 567

Identify the internal structural components of compact bone

Answer 567

- The dense outer shell of bone - Made up of subunits called osteons, which contain: 1) Lamellae - Columns of the matrix (mainly collagen) that are weight bearing - Run concentric, circumferential, and interstitially 2) Central (Haversian canal) - Contains blood vessels and nerves 3) Perforating (Volkmann’s) canals - Channels that connect blood and nerves from periosteum to the central (Haversian) canal; run transverse or diagonal.

Question 568

Osteons are made up of what 3 components?

Answer 568

Lamellae, central (haversian) canal, and perforating (volkmann’s) canals

Question 569

Identify the internal structural components of spongy bone

Answer 569

- A lattice of bone covered with endosteum and an internal honeycomb of trabeculae filled with red or yellow bone marrow - Trabeculae (thin plates of bone) develop along the bone’s lines of stress. - Spaces filled with red bone marrow - Few osteons and no central canals - Provides strength with minimal weight

Question 570

Describe and distinguish between the two types of bone marrow.

Answer 570

1) Red marrow - Contains hemopoietic tissue; produces blood cells. - Found in almost all bones in children, and found primarily in the axial skeleton of adults. 2) Yellow marrow - Found in adults - Stores triglycerides; functions as energy storage. - Can transform back to red marrow in the event of chronic anemia.

Question 571

Describe the intramembranous ossification mode of bone formation

Answer 571

- Bone develops within a fibrous connective tissue membrane - Mesenchymal cells >>> osteoblasts >>> osteocytes (spongy bone) - Forms the flat bones of the skull, clavicles, and ossifies the fontanels. - Most of these bones are remodeled (destroyed and reformed) as we grow to adult size. - Thickens long bones throughout our lives.

Question 572

Describe the endochondral ossification mode of bone formation

Answer 572

- Bone forms by replacing hyaline cartilage - Forms most the bones of the body below the skull (except the clavicle) - Mesenchyme >>turns into>> chondroblasts >> *die and are replaced by* >> osteoblasts >>turn into>> spongy bone >>turn into>> compact bone

Question 573

Compare and contrast the function of osteoblasts and osteoclasts during bone growth, repair, and remodeling.

Answer 573

- Osteoblasts: create bone - Osteoclasts: break down bone. - During bone growth, osteoblasts create bone. --During bone remodeling, osteoclasts break down bone and osteoblasts create bone.

Question 574

Name and describe the process by which minerals are added to bone tissue.

Answer 574

- Mineral deposition (mineralization): the process in which calcium, phosphate, and other ions are taken from blood and deposited in bone. - During this process, osteoblasts produce collagen fibers, and the collagen fibers then become encrusted with minerals. - The first few mineral crystals act as “seed crystals” that attract more calcium and phosphate

Question 575

Name and describe the process by which minerals are removed from bone tissue.

Answer 575

- Mineral resorption: the process of dissolving bone and releasing minerals into blood - This process is performed by osteoclasts; they pump hydrogen to extracellular fluid (chloride follows). Hydrochloric acid (pH 4) dissolves bone minerals. - They also produce an enzyme which digests collagen in an acidic environment.

Question 576

Describe the role of the bones in regulating blood calcium and phosphate levels.

Answer 576

- When blood calcium or phosphate is LOW, the process of mineral resorption takes place. For example, if blood calcium is low, then some of the calcium stored in the bones will be resorbed into the blood stream. - When blood calcium or phosphate is HIGH, the process of mineral deposition takes place. For example, if blood calcium is high, then some of the calcium from the blood stream will be deposited into the bones.

Question 577

Explain the role of calcitriol in regulation of bone physiology and describe its effect

Answer 577

- Calcitriol (aka vitamin D) is a hormone that raises blood calcium levels. - Mainly, it increases calcium absorption by the small intestine, but it also increases calcium resorption from the skeleton, and weakly promotes kidney reabsorption of calcium ions, so less are lost in urine. - It’s produced by actions of skin, liver, and kidneys. - Calcitriol is necessary for bone deposition, so lack of calcitriol results in abnormal softness of bones; in children, this causes rickets, and in adults, this causes osteomalacia.

Question 578

Explain the role of calcitonin in regulation of bone physiology and describe its effect

Answer 578

- Calcitonin is produced by the thyroid gland and lowers blood calcium levels; its release is triggered by high blood calcium. - It lowers blood calcium concentration in 2 ways; it inhibits osteoclasts and stimulates osteoblasts. - It’s important in children, but has a weak effect in adults (except may inhibit bone loss in pregnant and lactating women)

Question 579

Explain the role of parathyroid hormone in regulation of bone physiology and describe its effect

Answer 579

- Parathyroid hormone is produced by the parathyroid glands, and increases blood calcium; its release triggered by low blood calcium. - PTH increases blood calcium 4 ways; it stimulates osteoclast population and bone resorption, promotes calcium reabsorption by kidneys, promotes calcitriol synthesis, and inhibits osteoblasts, inhibiting bone deposition

Question 580

Explain the hormonal regulation of skeleton growth.

Answer 580

- Epiphyseal plate activity is stimulated by Human Growth Hormone (hGH); hGH stimulates growth at the epiphyseal plates in children. - Estrogen has a stronger effect on skeleton growth than testosterone; both of those hormones begin to affect bone growth during puberty, and they differentiate the male and female skeleton. - Males typically continue to grow for a longer period of time than females. - At least 20 or more hormones, vitamins, and growth factors affect osseous tissue. - Anabolic steroids administered during childhood/ adolescence can also prematurely stop bone growth.

Question 581

Describe the bone disease ostoporosis

Answer 581

- The most common bone disease - Affects spongy bone the most since it is the most metabolically active - Subject to pathological fractures of hip, wrist, and vertebral column - Kyphosis (widow’s hump): deformity of spine due to vertebral bone loss - Complications of loss of mobility are pneumonia and thrombosis - Estrogen maintains bone density in both sexes; inhibits resorption by osteoclasts - Postmenopausal white women are at the greatest risk; white women begin to lose bone mass as early as age 35. By age 70, their average loss is 30% of bone mass. - Osteoporosis also seen in young female athletes with low body fat causing them to stop ovulating and decrease estrogen secretion - Risk factors: race, age, gender, smoking, diabetes mellitus, diets poor which are poor in: calcium, protein, vitamins C and D - Treatments: Estrogen replacement therapy (ERT) (slows bone resorption, but increases risk of breast cancer, stroke, and heart disease); PTH derivative can also be used as a treatment but can cause bone cancer; certain medications destroy osteoclasts. - However, best treatment is prevention: exercise and a good bone-building diet between ages 25 and 40

Question 582

Describe the bone disease osteomalacia

Answer 582

Caused by low levels of calcitriol (vitamin D) in adults; leads to abnormally soft bones. This is because calcitriol is necessary for bone deposition.

Question 583

Describe the bone disease Ricket's

Answer 583

Caused by low levels of calcitriol (vitamin D) in children; leads to abnormally soft bones. This is because calcitriol is necessary for bone deposition.

Question 584

Describe the bone disease osteogenesis imperfecta

Answer 584

A deficit in collagen deposition.

Question 585

Name and describe the types of fractures.

Answer 585

- Non-displaced: A fracture where the bones remain aligned. - Displaced: A fracture where the bones become misaligned. - Comminuted: A fracture in which the bone breaks into several pieces - Greenstick: An incomplete fracture in which the bone is bent; occurs most often in children.

Question 586

Explain the ways in which a fracture can be repaired.

Answer 586

- Closed reduction: A procedure in which bone fragments are manipulated into their normal positions without surgery - Open reduction: Involves surgical exposure of the bone and the use of plates, screws, or pins to realign the fragments - Cast: normally used to stabilize and immobilize healing bone

Question 587

Explain how the body heals fractures

Answer 587

The body repairs fractures by forming a hematoma, then a soft callus, then a hard callus, then bone remodeling.

Question 588

Predict factors or situations affecting the skeletal system that could disrupt homeostasis.

Answer 588

- Lack of vitamin D in your diet could lead to osteomalacia, disrupting homeostasis. - Radiation therapy can cause damage to red bone marrow, which can lead to decreased blood cell production, which can lead to disruption of homeostasis.

Question 589

Predict the types of problems that would occur in the body if the skeletal system could not maintain homeostasis.

Answer 589

Lack of homeostatic control causes illness, injury, or death.