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MCAT > Bio: Ch 3, 10 > Flashcards

Bio: Ch 3, 10 Flashcards

1
Q

fertilization

A

joining of a sperm and an ovum

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2
Q

ampulla

A

widest part of the fallopian tube

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3
Q

where does fertilization usually occur

A

occurs in the ampulla of hte fallopian tube

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4
Q

how does fertilization happen?

A
  1. sperm uses acrosomal enzymes to penetrate the corona radiata and zona pellucida
  2. once it contacts the oocyte’s plasma membrane, the sperm establishes the acrosomal apparatus and injects is pronucleus
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5
Q

cortical reaction

A

occurs after penetration of sperm through cell membrane

  • sperm causes release of calcium ions –> prevents additional sperm from fertilizing the egg
  • increases the metabolic rate of the resulting diploid zygote
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6
Q

fertilization membrane

A

depolarized and impenetrable membrane after cortical reaction

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7
Q

fraternal (dizygotic) twins result from

A

fertilization of two eggs by two different sperm

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8
Q

identical (monozygotic) twins result from

A

splitting of a zygote in two

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9
Q

monozygotic twins vs dizygotic twins

placenta

A

monozygotic: one placenta
dizygotic: two separate

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10
Q

cleavage

A

early divisions of cells in the mebryo

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

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11
Q

zygote becomes an embryo after…

A

first cleavage because it is no longer unicellular

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12
Q

indeterminate cleavage

A

results in cells that are capable of becoming any cell in the organism

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13
Q

determinate cleavage

A

results in cells that are committed to differentiating into a specific cell type

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14
Q

morula

A

solid mass of cells seen in early development

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15
Q

blastulation

A

morula is formed into a blastula

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16
Q

blastula (blastocyst)

A

hollow ball of cells

blastocoel - fluid filled center

two different structures: trophoblast and inner cell mass

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17
Q

blastocoel

A

fluid filled center of blastula

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18
Q

trophoblast

A

part of blastula that surround the blastocoel

give rise to the chorion and later the placenta

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19
Q

inner cell mass

A

part of blastula

becomes the developing organism

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20
Q

what does the blastula do?

A

implants in the endometrial lining and forms the placenta

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21
Q

chorion

A

extraembryonic membrane that develops into the placenta

contains chorionic villi

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22
Q

chorionic villi

A

part of chorion

penetrate the endometrium and create the interface between maternal and fetal blood

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23
Q

before the placenta is established, the embryo is supported by…

A

the yolk sac

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24
Q

allantois

A

involved in early fluid exchange between embryo and yolk sac

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25
Q

amnion

A

lies just inside the chorion

produces amniotic fluid

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26
Q

umbilical cord

A

connects the developing organism to the placenta

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27
Q

gastrulation

A

generation of 3 distinct cell layers: ectoderm, mesoderm, endoderm

  • archenteron is formed with a blastopore at the end
  • as the archenteron grows through the blastocoel, it contacts the opposite side, establishing three primary germ layers
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28
Q

ectoderm becomes

A

skin, hair, nails, epithelia of nose, mouth, anal canal

nervous system

lens of the eye

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29
Q

mesoderm becomes

A

musculoskeletal, circulatory, and excretory system

gonads, adrenal cortex

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30
Q

endoderm becomes

A

epithelial linings of respiratory and digestive tracts

parts of pancreas, thyroid, bladder, and distal urinary tracts

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31
Q

neurulation

A

development of nervous system

notochord, neural tube, neural crest cells

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32
Q

what happens after gastrulation

A

neurlation

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33
Q

neurulation

notochord

A

induces group of overlying ectodermal cells to form neural folds surrounding a neural groove

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34
Q

neurulation

neural folds

A

fuse to form the neural tube

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35
Q

neural tube

A

becomes central nervous system

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36
Q

neural crest cells

A

becomes PNS and specific cell types in other tissues

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37
Q

teratogens

A

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

include: alc, certain drugs, viruses, bacteria, environmental chemicals

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38
Q

maternal conditions that can affect development

A

diabetes (inc fetal size and hypoglycemia after birth)

folic acid deficiency (neutral tube defects)

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39
Q

from zygote to gastrula, what are the various stages of development?

A
  1. zygote
  2. 2, 4, 8, 16 cell embryo
  3. morula
  4. blastula (blastocyst)
  5. gastrula
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40
Q

during which stage of development does implantation occur?

A

blastula stage

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41
Q

specification

A

inital stage of cell specialization

cell is reversibly designated as a specific cell type

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42
Q

cell specialization stages

A
  1. specification
  2. determination
  3. differentiation
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43
Q

determination

A

commitment to a specific cell lineage

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44
Q

pathways in which determination may occur

A
  • uneven segregation of cellular material during mitosis
  • morphogens
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45
Q

morphogens

A

cause neighboring cells to follow a particular developmental pathway

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46
Q

differentiation

A

the changes a cell undergoes due to selective transcription to take on characteristics appropriate to its cell type

cell assumes the structure, function, and biochem of that cell type

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47
Q

stem cells

A

cells that have not yet differentiated or that give rise to other cells that will differentiate

include: totipotent, pluripotent, multipotent

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48
Q

stem cells can be classified by…

A

potency

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49
Q

totipotent cells

A

able to differentiate into all cell types

including the 3 germ layers and placental structures

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50
Q

pluripotent cells

A

able to differentiate into all 3 of the germ layers and their derivatives

EXCEPT for those found in placental structures

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51
Q

multipotent cells

A

able to differentiate only into a specific subset of cell types

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52
Q

as cells become more differentiated, the potency of the cell ____

A

decreases

(from totipotent to pluripotent to multipotent)

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53
Q

inducer

A

releases factors to promote the differentiation of a component responder

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54
Q

responder

A

cell that is induced

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55
Q

to be induced, a responder must be…

A

competent

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56
Q

competent

A

able to respond to the inducing signal

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57
Q

autocrine signaling

A

acts on the same cell that released the signal

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58
Q

paracrine signalling

A

acts on local cells

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59
Q

juztacrine signalling

A

acts through direct stimulation of adjacent cells

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60
Q

endocrine signaling

A

acts on distant tissues after traveling through the blood stream

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61
Q

growth factors

A

peptides that promote differentiation and mitosis in certain tissues

includes most inducers

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62
Q

reciprocal induction

A

when two tissues both induce further differentiation in each other

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63
Q

most signalling occurs via…

A

gradients

(includes morphogens)

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64
Q

apoptosis

A

programmed cell death via the formation of apoptotic blebs that can subsequently be absorbed and digested by other cells

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65
Q

apoptosis can be used for…

A

sculpting certain anatomical structures - such as removing the webbing between digits

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66
Q

apoptotic blebs can be broken apart into ____ and…

A

apoptotic bodies and digested by other cells

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67
Q

necrosis

A

process of cell death in which a cell dies as a result of injury

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68
Q

regenerative capacity

A

ability of an organism to regrow certain parts of the body

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69
Q

regenerative capacity of liver

A

high

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70
Q

regenerative capacity of heart

A

low

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71
Q

complete regeneration

A

lost or damaged tissues are replaced with identical tissues

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72
Q

incomplete regernation

A

the newly formed tissue is not identical in structure or function to the tissue that has been injured or lost

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73
Q

senescence

A

biological aging

result of multiple molecular and metabolic process

includes shortening of telomeres during cell division

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74
Q

what occurs at the placenta

A

nutrient, gas, and waste exchange occurs

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75
Q

how are oxygen and carbon dioxide exchanged in fetus?

A

passively exchanged due to conc gradients

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76
Q

fetal hemoglobin (HbF)

A

has higher affinity for oxygen than adult hemoglobin

affinity assists in the transfer and retention of oxygen into the fetal circulatory system

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77
Q

placenta and immunity

A

placental barrier serves as immune protection against many pathogens

antibodies are transferred from mother to child

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78
Q

placenta and endocrine system

A

placenta serves endocrine functions

secretes estorgen, progesterone, and human chorionic gonadotropin (hCG)

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79
Q

umbilical arteries

A

carry deoxygenated blood from the fetus to the placenta

(unlike most arteries)

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80
Q

umbilical vein

A

carries oxygenated blood from the placenta back to the fetus

(unlike most veins)

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81
Q

differences between fetal and adult circulation

A

fetus:

  • three shunts (to direct blood away from organs as they develop)
  • lungs and liver do not serve significant functions before birth
  • gas exchange occurs at placenta
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82
Q

foramen ovale

A

fetal circulatory system

connects right atrium to left atrium, bypassing the lungs

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83
Q

ductus arteriosus

A

fetal circulatory system

connects pulmonary artery to aorta, bypassing the lungs

84
Q

ductus venosus

A

fetal circulatory system

connects umbilical vein to inferior vena cava, bypassing the liver

85
Q

what occurs during first trimester?

A

organogenesis: development of heart, eyes, gonads, limbs, liver, brain

86
Q

what occurs during second trimester?

A
  • tremendous growth
  • movement beings
  • face becomes distinctly human
  • digits elongate
87
Q

what occurs during third trimester?

A
  • rapid growth and brain development contue
  • transfer of antibodies to fetus
88
Q

parturition

A

vaginal childbirth

89
Q

afterbirth

A

placenta and umbilical cord are expelled

90
Q

what occurs during birth?

A
  1. cervix thins out
  2. amniotic sac ruptures
  3. uterine contractions, coordinated by prostaglandins and oxytocin
  4. afterbirth
91
Q

Are each of the following developing cell types Totipotent, Pluripotent, Multipotent, or Unipotent?

(1) Zygote cells
(2) Trophoblast cells
(3) Inner Cell Mass (ICM)

A

(1) Zygote cells are Totipotent.
(2) Trophoblast cells are Multipotent, only being able to form the cells found in the placenta.
(3) Inner Cell Mass (ICM) are Pluripotent, being able to form all cell types but those found in the placenta.

92
Q

Pre-synaptic neurons communicating with Post-synaptic Neurons across the Synapse is an example of which type of cell-cell communication?

(A) Paracrine Signaling
(B) Autocrine Signaling
(C) Juxtacrine Signaling
(D) Endocrine Signaling

A

(A) Paracrine Signaling

Pre-synaptic neurons communicating with Post-synaptic Neurons across the Synapse is an example of Paracrine Signaling in which a cell sends out a signal to nearby cells.

93
Q

Post-Mitotic Cells, as compared to Mitotic Cells, are likely in which stage of the cell cycle?

A

Post-Mitotic Cells are cells which can no longer undergo mitosis and divide into new cells. For this reason, these cells would be in G₀ of Interphase.

94
Q

What does it mean to say that a cell is Senescent?

A

It is basically a mitotic cell that no longer divides. It is a mitotic cell that has entered G₀ of Interphase.

95
Q

In what way is cells becoming senescent a good thing? Bad thing?

A

Cells becoming senescent is a good thing because it means that these cells will not become cancerous.

It is a bad thing because it leaves the tissue with a decreased ability to repair itself. Senescent cells are closely related to age-related diseases.

96
Q

When in the womb, a baby girl’s Oogonia divide and divide until their are between 2 to 4 million Oogonia. These Oogonia then begin to undergo Meiosis. At which point do they undergo “Meiotic Arrest”? What does that mean?

A

They will undergo Meiotic Arrest during Meiosis I. This basically means that the primary Oocytes are stuck in Meiosis I.

97
Q

At which point is a Primary Oocyte stimulated to finish Meiosis I? Meiosis II?

A

A Primary Oocyte stimulated to finish Meiosis I during ovulation and Meiosis II during Fertilization.

98
Q

Is the egg cell a primary or secondary oocyte when it is able to be fertilized? When does the transition to secondary oocyte occur?

A

The egg cell is a secondary oocyte when it is able to be fused with sperm.
In the ovary, the primary oocyte that escape meiotic arrest will divide into a secondary oocyte and another polar body

99
Q

True or false? Chorionic Villi are almost like villi in the small intestine for the fetus in the basal plate, since they protrude into the basal plate, increase the surface area and facilitate the exchange of gases and nutrients.

A

True. Chorionic Villi are almost like villi in the small intestine for the fetus in the basal plate, since the protrude into the basal plate, increase the surface area and facilitate the exchange of gases and nutrients.

100
Q

Which Uterine Phase is the longest, lasting 14 days out of 28 days?

(A) Menses
(B) Proliferative Phase
(C) Secretory Phase
(D) None of the above

A

(C) Secretory Phase

The Secretory Phase is the longest of the Uterine Phases, lasting 14 of the 28 days.

101
Q

Which hormone directly triggers ovulation?

(A) Estrogen
(B) LH
(C) FSH
(D) Progesterone

A

(B) LH

LH pushes the development of the follicle to trigger ovulation.

102
Q

If a blastocyst undergoes implantation, it creates human chorionic gonadotropin (hCG) to keep the corpus luteum alive. hCG mimics which hormone?

(A) Estrogen
(B) Luteinizing hormone
(C) Progesterone
(D) Inhibin

A

(B) Luteinizing hormone

hCG mimics LH to keep the corpus luteum alive to be able to allow estrogen/progesterone to keep the endometrial lining for pregnancy.

103
Q

Explain why you need to keep the endometrial lining intact for pregnancy.

A

The Endometrial Lining is where the blastocyst implants!

104
Q

Which of the following occur in response to the increased amount of estrogen during pregnancy?

I. Suppress of FSH & LH
II. Growth of fetal organs
III. Maternal tissue growth

(A) I only
(B) II and III only
(C) I and II only
(D) I, II, and III only

A

(D) I, II, and III only

Estrogen during pregnancy allows for:

  • suppression of FSH and LH
  • growth of fetal organs
  • maternal tissue growth
105
Q

Match each of the following effects to either FSH, LH or neither.

I. Stimulate Sertoli Cells
II. Stimulate Leydig Cells
III. Trigger Sperm Maturation
IV. Stimulates Inhibin Production
V. Increases Seminiferous Tubule Development

A

I. Stimulate Sertoli Cells - FSH
II. Stimulate Leydig Cells - LH
III. Trigger Sperm Maturation - FSH
IV. Stimulates Inhibin Production - FSH
V. Increases Seminiferous Tubule Development - FSH

106
Q

Put the following processes in order from first to last:

I. Implantation
II. Fertilization
III. Gestation
IV. Parturition

(A) I > II > III > IV
(B) II > I > III > IV
(C) IV > III > II > I
(D) IV > III > I > II

A

(B) II > I > III > IV

In order from first to last:

Fertilization > Implantation > Gestation > Parturition

107
Q

What is the difference between Fertilization and Implantation?

A

Fertilization is the process by which the ovum and sperm join together, forming a Zygote.

Implantation describes the joining of the Zygote with the wall of the uterus.

108
Q

When it is warm outside, how does the body regulate the position of the scrotum? What about when it is cold outside?

A

When it is warm outside, the body will cause the scrotum to hang down lower away from the body in order to decrease the temperature in the testes.

When it is cold outside, the body will cause the scrotum to retract up into the body in order to increase the temperature in the testes.

109
Q

Briefly explain the functionality of the following accessory glands in terms of reproduction:

(1) Prostate Gland
(2) Bulbourethral Gland
(3) Seminal Vesicles

A

All of them contribute more fluid to the semen. In addition:

(1) Prostate Gland - Produces prostatic fluid which increases the motility of sperm.
(2) Bulbourethral Gland - Adds a thick lubricant for the urethra and vagina.
(3) Seminal Vesicles - creates a basic environment to neutralize the acidic environment of the urethra and vagina.

110
Q

In creating sperm, there are two processes – mitosis and meiosis. Using the following terms, describe the start and end of mitosis and meiosis.

I. Spermatogonia
II. Spermatids
III. Spermatocytes
IV. Sperm

A

Mitosis starts with spermatogonia and ends with primary spermatocytes.

Meiosis starts with primary spermatocytes and ends with spermatids.

Spermatids will then develop and grow into sperm.

111
Q

Adult human cells have 46 chromosomes. How many chromosomes should you find in each of the following cell types?

(1) Spermatogonia
(2) Primary Spermatocytes
(3) Secondary Spermatocytes
(4) Spermatids
(5) Sperm

A

(1) Spermatogonia - 46
(2) Primary Spermatocytes - 46
(3) Secondary Spermatocytes - 23
(4) Spermatids - 23
(5) Sperm - 23

112
Q

What are the main functions of testosterone in the male reproductive tract?

I. Makes reproductive organs male
II. Promotes sperm production
III. Inhibits female reproductive organ development

(A) I Only
(B) II Only
(C) I and II Only
(D) II and III Only

A

(C) I and II Only

Testosterone acts to make the reproductive organs male in a developing fetus. Testosterone also aids in promoting sperm production.

113
Q

True or False? Almost all of your mitochondria originates from your mom.

A

True. Almost all of your mitochondria originates from your mom. The sperm has very few mitochondria compared to the egg.

114
Q

When a single egg cell is fertilized by a sperm, the result is a:

(A) Morula
(B) Blastocyst
(C) Trophoblast
(D) Zygote

A

(D) Zygote

A zygote is formed when a single egg cell is fertilized by a sperm.

115
Q

Put the following steps in order from first to last:

I. Blastulation
II. Cleavage
III. Neurulation
IV. Gastrulation
V. Fertilization
VI. Implantation

(A) V > IV > I > II > III > VI
(B) V > III > IV > I > II > VI
(C) V > II > I > VI > IV > III
(D) V > IV > I > VI > II > III

A

(C) V > II > I > VI > IV > III

The following steps of embryogenesis are in order from first to last:

V. Fertilization
II. Cleavage
I. Blastulation
VI. Implantation
IV. Gastrulation
III. Neurulation

116
Q

During cleavage, the zygote doesn’t grow but rather splits into multiple cells in a process known as cleavage. At what point does the zygote become known as morula? At what point does the morula become known as a blastula?

A

When the zygote has divided into 16 different cells, it is known as a morula.

The morula becomes known as a blastula once a hollow cavity develops.

117
Q

CRB True or false? Conjoined Twins result from failures in the Cleavage Stage.

A

False.
Conjoined Twins result from a failed, partial-division in the zygote stage before cleavage.
If this division had been successful, monozygotic twins would have been born.

118
Q

CRB Compare Indeterminate and Determinate Cleavage. Which can form monozygotic twins?

A

Indeterminate Cleavage will produce cells that could still develop into complete organisms, and could form monozygotic twins.
Determinate Cleavage produces cells that are committed to a certain cell lineage.

119
Q

As the amniotic cavity begins to develop within the Inner Cell Mass, the blastocoel becomes a primitive version of the:

(A) Amion
(B) Chorion
(C) Yolk Sac
(D) Placenta

A

(C) Yolk Sac

As the amniotic cavity begins to develop within the Inner Cell Mass, the blastocoel becomes a primitive version of the yolk sac.

120
Q

The notochord develops within the ______________. The neural plate develops within the ______________.

(A) Ectoderm, Mesoderm
(B) Mesoderm, Ectoderm
(C) Endoderm, Mesoderm
(D) Mesoderm, Endoderm

A

(B) Mesoderm, Ectoderm

The notochord develops within the mesoderm. The neural plate develops within the ectoderm.

121
Q

excretory system functions

A
  1. regulation of
    1. blood pressure
    2. blood osmolarity
    3. acid base balance
  2. removal of nitrogenous wastes
122
Q
A

cortex and medulla

hilium - contains renal artery, renal vein, ureter

123
Q

kidney

A

produces urine

124
Q

urine journey

A

kidney > ureter > bladder > urethra

125
Q

renal hilium

A

part of kidney

deep slit in center of ikidney’s medial surface

126
Q

penal pelvis

A

widest part of ureter

127
Q

kidney structure

A

cortex and medulla

hilium - contains renal artery, renal vein, ureter

128
Q

portal system

A

two capillary beds in series through which blood must travel before returning to the heart

129
Q

portal system

blood flow

A

blood from renal artery > afferent arterioles > glomeruli in bowman’s capsule (1st capillary bed) > efferent arteriole > vasa recta (second capillary) > renal vein

130
Q

glomeruli

A

highly convoluted capillary tufts derived from afferent arterioles

131
Q

vasa recta

A

capillaries that surround the loop of henle

132
Q

detrusor muscle

+nervous system control?

A

muscular lining of the bladder

under parasympathetic control

133
Q

internal urethral sphincter

A

smooth muscle

under parasympathetic (involuntary) control

134
Q

external urethral sphincter

A

skeletal muscle

under voluntary control

135
Q

urination process

A
  1. bladder full –> stretch receptors tell nervous system
  2. detrusor muscle contracts
  3. internal sphincter relaxes (micturiton reflex)
  4. person chooses next:
    1. relax external sphincter to urinate
    2. can maintain external sphincter to prevent urination
  5. abdominal muscles contract –> bladder compressed –> urination
136
Q

processes that allow the kidneys to participate in solute movement

A
  • filtration
  • secretion
  • reabsorption
137
Q

filtration

A

movement of solutes from blood to filtrate at bowman’s capsule

direction and rate of filtration determined by starling forces

138
Q

starling forces

A

governs movement of fluid into bowman’s space

accounts for pressure differential in both hydrostatic and oncotic pressures between the blood and bowman’s space

139
Q

hydrostatic pressure in glomerulus is ___ than that in Bowman’s space, which causes fluid to move into…

A

higher

nephron

140
Q

osmolarity of blood in glomerulus is ___ than that of bowman’s space, resulting in pressure…

A

higher

opposing the movement of fluid into the nephron

141
Q

hydrostatic pressure in glomerulus is ____ than oncotic pressure, so net flow of blood is…

A

larger

into th enephron

142
Q

secretion

A

movement of solutes from blood to filtrate anywhere other than bowman’s capsule

143
Q

readsorption

A

movement of solutes from filtrate to blood

taken back up for use

144
Q

what kinds of substances would be readsorbed?

A

glucose, amino acids, vitamins, hormones

145
Q

two main goals of kidney

A
  1. keep what body needs and lost what it doesn’t
  2. concentrate urine to conserve water
146
Q

major waste products excreted in urine

A

dump the HUNK

H+, urea, NH3, N+

147
Q

solutes that enter the interstitium…

A

picked up by vasa recta to be turned to blood for reuse in body

148
Q

interstitium

A

connective tissue surrounding the nephron

149
Q

proximal convoluted tube (PCT)

A

site of bulk readsorption of glucose, amino acids, soluble vitamins, salt, water

site of secretion for hydrogen ions, potassium ions, ammonia, and urea

150
Q

descending limb of loop of henle

A

permeable to water but not salt –> as filtrate moves into more osmotically concentrated renal medulla, water is reabsorbed from filtrate

151
Q

countercurrent mutiplier system

A

vasa recta and nephron flow in opposite directions –> allows for maximal readsorption of water

152
Q

ascending limb of loop of henle

A

permeable to salt but not water –> salt is readsorbed both passively and actively

diluting segment

153
Q

diluting segment

A

in outer medulla

filtrate becomes hypotonic compared to blood

154
Q

collecting duct

A

responsive to both aldosterone and ADH

has variable permeability –> allows for reabsorption of the right amount of water depending on the body’s need

155
Q

distal convoluted tubule (DCT)

A

responsive to aldosertone

site of salt reabsorption and wast product excretion, like the PCT

156
Q

hormone systems that are activated when blood pressure and volume are low

A

aldosterone

ADH/vasopressin

157
Q

aldosterone

type of hormone

A

steroid hormone

158
Q

ADH

type of hormone

A

peptide hormone

159
Q

how does kidney regulate pH?

A

selective readsorption or secretion of bicarbonate or hydrogen ions

160
Q

aldosterone

regulated by

A

regulated by renin-angiotensin-aldosterone system

161
Q

aldosterone

kidney functions

A

increases sodium reabsorption in distal convoluted tubule and collecting duct –> increases water readsorption –> increase blood volume, with no change in blood osmolarity

162
Q

ADH

synthesized by

A

synthesized by hypothalamus and released by posterior pituitary

163
Q

ADH

release is stimulated by…

A

release is stimulated by low blood volume and high blood osmolarity

164
Q

ADH

kidney function

A

increases permeability of collecting duct to water –> increasing water readsorption –> increases blood volume and decreases blood osmolarity

165
Q

layers of skin

A

hypodermis (subcutaneous layer)

dermis

epidermis

166
Q

epidermis layers

A

Come, Let’s Get Sun Burned

  1. stratum corneum
  2. stratum lucidum
  3. stratum granulosum
  4. stratum spinosum
  5. stratum basale
167
Q

stratum basale

A

contains stem cells that proliferate to form keratinocytes

168
Q

keratinocytes

A

produce keratin

169
Q

stratum spinosum

A

site of langerhans cells

170
Q

stratum granulosum

A

where keratinocytes die and lose their nuclei

171
Q

stratum lucidum

A

only present in thick, hairless skin

172
Q

stratum corneum

A

contains several dozen layers of flattened keratinocytes

173
Q

melanocytes

A

produce melanin

174
Q

melanin

A

protects the skin from DNA damage caused by UV radiation

175
Q

Langerhans cells

A

special macrophages that serve as antigen presenting cells in the skin

176
Q

dermis layers

A
  1. papillary layer
  2. reticular layer
177
Q

hypodermis

A

contains fat and connective tissue and connects the skin the the rest of the body

178
Q

sensory cells in dermis

A

merkel cells, free nerve endings, meissner’s corpuscles, ruffini endings, pacinian corpuscles

179
Q

sweating

A

draws heat form the body through evaporation of water from weat

180
Q

sweat glands are innervated by…

A

postganglionic cholinergic sympathetic neurons

181
Q

cooling mechanism of skin

A
  • sweating
  • vasodilation
182
Q

warming mechanisms of skin

A
  • piloerection
  • casoconstriction
  • shivering
  • fat insulation
183
Q

piloerection

A

arrector pili muscles contract –> hairs stand on end –> trap layer of warmed air around skin

184
Q

skin prevents…

A

dehydration and salt loss from body

185
Q

fingernails and hair are formed from

A

keratin

186
Q

merkel cells

A

sensory receptors - deep pressure and texture sentation

187
Q

meissner’s corpuscles

A

respond to light touch

188
Q

free nerve endings

A

respond to pain

189
Q

ruffini endings

A

respond to stretch

190
Q

pacinian corpuscles

A

responds to deep pressure and vibration

191
Q

Which of the following can be thought of as a precursor to aldosterone?

(A) Cholesterol
(B) ADH
(C) Cortisol
(D) Testosterone

A

(A) Cholesterol

Upon receiving appropriate triggers, cholesterol is converted into aldosterone

192
Q

Which of the following is the main site of filtration in the kidney?

(A) Distal convoluted tubule
(B) Loop of Henle
(C) Proximal convoluted tubule
(D) Glomerulus

A

(D) Glomerulus

The glomerulus is the main site of filtration.

193
Q

What is the order of the parts of the nephron from first to last in terms of the direction of fluid flow?

I. Distal convoluted tubule
II. Proximal convoluted tubule
III. Collecting duct
IV. Bowman’s Capsule
V. Loop of Henle

(A) IV > V > II > I > III
(B) IV > I > II > V > III
(C) IV > II > V > I > III
(D) IV > V > I > II > III

A

(C) IV > II > V > I > III

The order of the parts of the nephron from first to last in terms of the direction of fluid flow is as follows:

Bowman’s Capsule > Proximal convoluted tubule > Loop of Henle > Distal convoluted tubule > Collecting duct

194
Q

The fluid that is filtered in the glomerulus empties into which of the following structures?

(A) Bowman’s Capsule
(B) Loop of Henle
(C) Proximal convoluted tubule
(D) Glomerulus

A

(A) Bowman’s Capsule

The glomerulus is the main site of filtration and the filtrate empties into bowman’s capsule.

195
Q

The countercurrent multiplication system is based on the idea that _______________ is/are reabsorbed in the descending limb and _______________ is/are reabsorbed in the ascending limb. Explain why this allows for the absorption of a great deal of water.

A

The countercurrent multiplication system is based on the idea that water is reabsorbed in the descending limb and salts are reabsorbed in the ascending limb. By actively transporting salts into the interstitium, a high osmotic pressure is created. This high osmotic pressure will suck water out of the descending limb as the filtrate travels through it.

196
Q

In which part of the Nephron would you find the Diluting Segment, which has thicker lining of the tubules and can actually produce urine more dilute than the blood?

(A) Proximal Convoluted Tubule
(B) Ascending Loop of Henle
(C) Descending Loop of Henle
(D) Distal Convoluted Tubule

A

(B) Ascending Loop of Henle

The Ascending Loop of Henle has the Diluting Segment, which has thicker lining of the tubules and can actually produce urine more dilute than the blood.

197
Q

In the bloodstream, bicarbonate will cause the formation of which of the following products?

I. CO2
II. H2O
III. H+

(A) III only
(B) II only
(C) I and II only
(D) I and III only

A

(C) I and II only

HCO3- will combine with a proton to form CO2 and water.

198
Q

To reinforce the Bicarbonate Buffer System, draw out the Bicarbonate Buffer System Equilibrium.

A
199
Q

Which of the following can the kidney selectively increase or decrease, depending on the pH of the blood?

(A) H+
(B) HCO3-
(C) Both A and B
(D) Neither A nor B

A

(C) Both A and B

Both H+ and HCO3- can be selectively increased or decreased by the kidney to return to homeostasis.

200
Q

Which of the following trigger the release of ADH from the pituitary gland?

I. Increased Blood Osmolarity
II. Increased Blood Volume
III. Increased Blood Pressure

(A) I Only
(B) II Only
(C) I and II Only
(D) I and III Only

A

(A) I Only

The triggers of ADH release are as follows:

  • Increased blood osmolarity (increased number of dissolved particles in the blood).
  • DECREASED blood volume.
  • DECREASED blood pressure.
  • Also remember that angiotensin II will trigger the release of ADH.
201
Q

Which of the following does the Integumentary System include?

I. Glands
II. Skin
III. Hair

(A) II Only
(B) I and II Only
(C) II and III Only
(D) I, II, and III

A

(D) I, II, and III

The Integumentary System includes the following:

(1) Skin
(2) Appendages such as nails, hair, and glands

202
Q

True or False? Your skin is impermeable to things such as water and viruses.

A

True. Your skin is impermeable to things such as water and viruses.

203
Q

In an effort to protect your body from foreign invaders, your skin secretes which of the following?

I. Langerhans Cells
II. Antibodies
III. Lysozyme

(A) I Only
(B) II Only
(C) I and II Only
(D) II and III Only

A

(D) II and III Only

Your skin secretes Lysozyme and Antibodies.

Langerhans cells are located within your skin. They are not secreted.

204
Q

In which layer of the epidermis do the keratinocytes begin to shrivel and become interconnected?

(A) Stratum Lucidum
(B) Stratum Granulosum
(C) Stratum Spinosum
(D) Stratum Basale

A

(C) Stratum Spinosum

Remember, this layer of skin is known as the “spinosum” because the shriveled, connected keratinocytes look like a spiny star.

205
Q

The dermis has two layers: the papillary dermis and the reticular dermis. Which of these two layers is the most superficial?

A

The papillary dermis is the most superficial layer of the reticular dermis and is just below the stratum basale layer of the epidermis.

MCAT (26 decks)

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