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Physiology Flashcards

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1
Q

When skeletal muscle contracts, the Z lines:

a. come closer together.
b. move farther apart.
c. remain at a constant distance.
d. none of the above.

A

a. come closer together

Z-lines denote the boundary of a sarcomere, which shrink when muscle contracts.

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2
Q

When skeletal muscle contracts, the sarcomere’s H-zone:

a. shortens.
b. lengthens.
c. remains unchanged.
d. none of the above.

A

a. shortens.

H-zone contains only thick filaments. During muscle contraction, thick filaments increasingly overlap with thin filaments, so region corresponding to only thick filaments shrinks.

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3
Q

When skeletal muscle contracts, the sarcomere’s A-zone:

a. shortens.
b. lengthens.
c. remains unchanged.
d. none of the above.

A

c. remains unchanged.

A-band denotes region of sarcomere which contains thick filaments regardless of the presence of thin filaments.

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4
Q

Which of the following correctly describes the role of calcium during muscle contraction?

a. Calcium binds to tropomyosin, causing troponin to cover the myosin binding site of actin.
b. Calcium binds to troponin, causing tropomyosin to cover the myosin binding site of actin.
c. Calcium binds to tropomyosin, causing troponin to exit the myosin binding site of actin.
d. Calcium binds to troponin, causing tropomyosin to exit the myosin binding site of actin.

A

d. Calcium binds to troponin, causing tropomyosin to exit the myosin binding site of actin.

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5
Q 
The function of which of the following is to transmit an action potential inside of a myocyte?
a. Sarcoplasmic reticulum
b. Sarcomere
c. T Tubules
D. Motor end plate
A

C. T Tubules

After AP has propagated along sarcolemma of myocyte, it moves deep into muscle cell via small infoldings of sarcolemma called T Tubules

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6
Q

Which of the following describes the events that occur inside of a myocyte after contraction?

a. The myocyte uses a concentration gradient to actively transport calcium into the cytosol
b. The myocyte uses ATP to actively transport calcium into the cytosol
c. The myocyte uses a concentration gradient to actively transport calcium into the sarcoplasmic reticulum
d. The myocyte uses ATP to actively transport calcium into the sarcoplasmic reticulum

A

d. The myocyte uses ATP to actively transport calcium into the sarcoplasmic reticulum

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7
Q

During the myosin/actin cross-bridge cycle, which of the following occurs?

a. The binding of ATP to myosin causes myosin to bind actin
b. ATP hydrolysis causes the myosin head to enter the “cocked” high energy state
c. ATP dissociation from myosin causes the power stroke
d. None of the above

A

b. ATP hydrolysis causes the myosin head to enter the “cocked” high energy state

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8
Q

A motor unit is:

a. a single myocyte and all of the neurons which innervate it
b. a single motor neuron and all of the muscle cells which it innervates
c. a collection of closely related muscles which accomplish a similar function
d. a collection of closely related motor neurons which accomplish a similar function

A

b. a single motor neuron and all of the muscle cells which it innervates

All of the fibers will be of the same type. When a motor unit is activated, all of its fibers contract. Groups of motor units often work together to coordinate the contractions of a single muscle

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9
Q

Which of the following correctly describes Type 1 and Type 2 muscle fibers?

a. Type 1 fibers produce a large amount of force
b. Type 1 fibers fatigue quickly
c. Type 2 fibers have lower mitochondrial content
d. Type 2 fibers are more oxygen dependent

A

c. Type 2 fibers have lower mitochondrial content

Type 2 fibers are fast-twitch fibers

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10
Q

Which hormone is secreted by the adrenal gland and increases blood pressure?

a. Antidiuretic hormone
b. Aldosterone
c. Renin
d. Angiotensinogen

A

b. Aldosterone

Aldosterone secreted by the adrenal gland increases the reabsorption of water and sodium thereby increasing blood volume

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11
Q

After production in the nephron, urine is delivered to which of the following?

a. Renal pelvis
b. Glomerulus
c. Vasa recta
d. Distal convoluted tubule

A

a. Renal pelvis

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12
Q

Which cell type forms the semipermeable filtration barrier of the glomerulus?

a. Mesangial cells
b. Podocytes
c. Adipocytes
d. Hepatocytes

A

b. Podocytes

Podocytes are cells that have food processes which extend along glomerular fenestrated epithelium and basement membrane forming filtration barrier

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13
Q

Which of the following is not a step involved in urine formation?

a. Glomerular filtration
b. Tubular filtration
c. Tubular reabsorption
d. Tubular secretion

A

b. Tubular filtration

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14
Q

Which of the following will increase the rate of urine formation?

a. Increasing hydrostatic pressure within the glomerulus
b. Increasing hydrostatic pressure within the bowman’s capsule
c. Decreasing oncotic pressure within the bowman’s capsule
d. All of the above

A

a. Increasing hydrostatic pressure within the glomerulus

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15
Q

The juxtaglomerular complex of the kidney secretes which hormone?

a. Aldosterone
b. Antidiuretic hormone
c. Renin
d. Angiotensin I

A

c. Renin

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16
Q

The presence of which of the following in the distal convoluted tubule leads to the reabsorption of water?

a. Presence of podocytes
b. Presence of acinar cells
c. Presence of mesangial cells
d. Presence of aquaporins

A

d. Presence of aquaporins

Aquaporins are water channels present on apical side of epithelial cells in distal convoluted tubules

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17
Q

Which of the following correctly describes the events that occur at the neuromuscular junction/motor end plate?

a. An action potential is initiated and transmitted by voltage gated sodium channels.
b. An action potential is initiated and transmitted by ligand gated sodium channels.
c. An action potential is initiated by the opening of ligand gated sodium channels and transmitted by voltage gated sodium channels.
d. An action potential is initiated by the opening of voltage gated sodium channels and transmitted by ligand gated sodium channels.

A

c. An action potential is initiated by the opening of ligand gated sodium channels and transmitted by voltage gated sodium channels.

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18
Q

Where is the majority of vitamin B12 absorbed?

a. Jejunum
b. Ileum
c. Colon
d. Duodenum

A

b. Ileum

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19
Q

Which of the following must occur prior to absorption of vitamin B12?

a. Denaturing due to HCl
b. Complexing with intrinsic factor
c. Cleavage due to pepsin
d. Cleavage due to pancreatic nuclease

A

b. Complexing with intrinsic factor

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20
Q

A patient had his gallbladder removed. Which type of food should he now try to limit in his diet?

a. Starch
b. Carbohydrates
c. Protein
d. Fat

A

d. Fat

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21
Q

Which of the following accurately describes thyroid hormone?

a. Released from the anterior pituitary
b. Binds to receptors on the outside of the cell
c. Derived from cholesterol
d. Binds to receptors on the inside of the cell

A

d. Binds to receptors on the inside of the cell

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22
Q

Which of the following is both an endocrine and exocrine gland?

a. Parathyroid Glands
b. Liver
c. Thyroid Gland
d. Adrenal Glands

A

b. Liver

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23
Q

The primary role of the parathyroid gland is:

a. To send hormonal signals to other endocrine organs
b. To receive hormonal signals from the hypothalamus
c. To maintain metabolic homeostasis
d. To regulate serum calcium levels

A

d. To regulate serum calcium levels

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24
Q

Which hormone is secreted by the adrenal gland and increases blood pressure?

a. Antidiuretic hormone
b. Aldosterone
c. Renin
d. Angiotensinogen

A

b. Aldosterone

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25
Q

After production in the nephron, urine is delivered to which of the following?

a. Renal pelvis
b. Glomerulus
c. Vasa recta
d. Distal convoluted tubule

A

a. Renal pelvis

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26
Q

Which of the following is not a step involved in urine formation?

a. Glomerular filtration
b. Tubular filtration
c. Tubular reabsorption
d. Tubular secretion

A

b. Tubular filtration

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27
Q

Which of the following will increase the rate of urine filtration?

a. Increasing hydrostatic pressure within the glomerulus
b. Increasing hydrostatic pressure within the bowman’s capsule
c. Decreasing oncotic pressure within the bowman’s capsule
d. All of the above

A

a. Increasing hydrostatic pressure within the glomerulus

28
Q

The juxtaglomerular complex of the kidney secretes which hormone?

a. Aldosterone
b. Antidiuretic hormone
c. Renin
d. Angiotensin I

A

c. Renin

29
Q

What coagulation factor is common to both the intrinsic and extrinsic pathway?

a. VII (proconvertin/stable factor)
b. VIII (antihemophilic factor A)
c. X (Stuart-Prower factor)
d. IX (Antihemophilic factor B/Christmas factor)

A

c. X (Stuart-Prower factor)

30
Q

How would an increase in bicarbonate (HCO3-) relative to all other molecules in the blood affect the oxygen affinity of hemoglobin and why?

a. Decrease oxygen affinity by binding with free protons
b. Decrease oxygen affinity by directly binding with hemoglobin
c. Increase oxygen affinity by directly binding with hemoglobin
d. Increase oxygen affinity by binding with free protons

A

d. Increase oxygen affinity by binding with free protons

31
Q

An individual with blood type O- could potentially have which blood antibodies present in their plasma?

a. B antibodies only
b. Neither A or B antibodies
c. Both A and B antibodies
d. A antibodies only

A

c. Both A and B antibodies

32
Q

Septic shock is a serious condition resulting from the body’s response to systemic bacterial infections, which may impair oxygen uptake and delivery. What physiological change may result from septic shock which would decrease the ability of hemoglobin in the alveolar capillaries to become fully saturated with oxygen?

a. Decreased afferent capillary pO2
b. Decreased alveolar wall thickness
c. Increased capillary blood flow
d. Increased blood pH

A

c. Increased capillary blood flow

33
Q

In a situation where the respiratory bronchioles become inflamed and narrowed, such as is seen in asthma, which aspect of respiration would be most mechanically impaired?

a. Normal expiration
b. Forced inhalation
c. Normal inhalation
d. Forced expiration

A

d. Forced expiration

34
Q

What is the pressure of gas within the alveoli at the peak of inspiration, just before expiration, relative to that of atmospheric air?

a. Less than atmospheric air
b. Greater than atmospheric air
c. Cannot be predicted without more information
d. The same as atmospheric air

A

d. The same as atmospheric air

35
Q

How might central and peripheral chemoreceptors compare with regard to their role in the detection of respiratory gases resulting from a prolonged period of hypoventilation?

a. Central chemoreceptors and peripheral chemoreceptors may both respond to the resultant decrease in pO2, but only peripheral chemoreceptors could respond to the increase in pCO2
b. Central chemoreceptors and peripheral chemoreceptors may both respond to the resultant increase in pO2, but only peripheral chemoreceptors could respond to the decrease in pCO2
c. Central chemoreceptors and peripheral chemoreceptors may both respond to the resultant decrease in pCO2, but only peripheral chemoreceptors could respond to the increase in pO2
d. Central chemoreceptors and peripheral chemoreceptors may both respond to the resultant increase in pCO2, but only peripheral chemoreceptors could respond to the decrease in pO2

A

d. Central chemoreceptors and peripheral chemoreceptors may both respond to the resultant increase in pCO2, but only peripheral chemoreceptors could respond to the decrease in pO2

36
Q

The lining of lymphatic vessels is composed of which of the following cell type?

a. simple squamous epithelium
b. simple cuboidal epithelium
c. stratified squamous epithelium
d. stratified cuboidal epithelium

A

a. simple squamous epithelium

37
Q

Lymph from which of the following parts of the body does not enter into the systemic circulation through the thoracic duct?

a. Lymph from the left arm
b. Lymph from the right arm
c. Lymph from the lower body
d. Lymph from the left side of the head

A

b. Lymph from the right arm

38
Q

Which of the following produces fructose to nourish sperm?

a. Seminal vesicles
b. Bulbourethral gland
c. Testes
d. Prostate gland

A

a. Seminal vesicles

39
Q

Which of the following correctly orders structures through which sperm exit during ejaculation?

a. Vas deferens -> Urethra -> Epididymis
b. Seminiferous Tubules -> Epididymis -> Urethra
c. Urethra -> Vas deferens -> Epididymis
d. Vas deferens -> Testes -> Urethra

A

b. Seminiferous Tubules -> Epididymis -> Urethra

Full order: Seminiferous Tubules, Epididymis, Vas deferens, Urethra, Penis

40
Q

Which order correctly describes the order of egg development?

a. Oogonia -> Primary oocyte -> Secondary oocyte -> Ovum
b. Primary oocyte -> Secondary oocyte -> Ovum -> Oogonia
c. Primary oocyte -> Secondary oocyte -> Oogonia -> Ovum
d. Ovum -> Primary oocyte -> Secondary oocyte -> Oogonia

A

a. Oogonia -> Primary oocyte -> Secondary oocyte -> Ovum

41
Q

A mature sperm is called a:

a. spermatid
b. spermatogonia
c. spermatocyte
d. spermatozoon

A

d. spermatozoon

42
Q

What is the function of LH during the ovarian cycle in females?

a. Forms the uterine lining
b. Causes ovulation
c. Maintains the uterine lining after pregnancy
d. Inhibits FSH

A

b. Causes ovulation

43
Q

LH and FSH are released from which gland?

a. Adrenal cortex
b. Adrenal medulla
b. Posterior pituitary
d. Anterior pituitary

A

d. Anterior pituitary

44
Q

What is the role of the uterine lining?

a. Allows for implantation of sperm
b. Allows for implantation of the fertilized egg
c. Allows for the implantation of the corpus luteum
d. Both B and C

A

b. Allows for the implantation of the fertilized egg

45
Q

Myelogenous leukemias are caused by the cancerous production of innate (non-specific) immune system cells: in which tissue is such production most likely to occur?

a. Bone marrow
b. Thymus
c. Spleen
d. Lymph nodes

A

a. Bone marrow

46
Q

Which of the following cell types of the innate immune system does not perform phagocytosis?

a. Macrophages
b. Basophils
c. Neutrophils
d. Eosinophils

A

b. Basophils

47
Q

Which of the following has a rate of urinary excretion (units of solute per unit time) that is always much lower than its rate of glomerular filtration in a healthy adult?

a. Glucose
b. Sodium
c. Potassium
d. Urea

A

a. Glucose

48
Q

The following may or may not be steps included in the endochondral ossification of long bones:

I. Ossification of the epiphyses
II. Ossification of the diaphysis
III. Intramembranous ossification
IV. Formation of the epiphyseal plate
V. Formation of a hyaline cartilage model

What is the correct sequence of events in ossification of a long bone?

a. V -> I -> II -> IV
b. III -> II -> I -> IV
c. V -> II -> I -> IV
d. V -> III -> I -> II -> IV

A

c. V -> II -> I -> IV

49
Q

People with albinism have a defect in tyrosinase, an oxidase that helps to control skin pigment production. In what epidermal layer is tyrosinase active?

a. Stratum granulosum
b. Stratum spinosum
c. Stratum basale
d. Stratum lucidum

A

c. Stratum basale

50
Q

Which of the following is NOT a feature of the stratum granulosum?

a. Cells in this layer contain keratohyaline granules
b. There are 3-5 layers of cells in this layer
c. Cytokeratin is produced in this layer
d. The cells of this layer secrete a lipid, waterproof layer

A

c. Cytokeratin is produced in this layer

51
Q

The skeletal system contributes to the production of which of the following cells?

a. Erythrocytes
b. Hepatocytes
c. Neurons
d. Microglia

A

a. Erythrocytes

52
Q

Which of the following does not compose the mineral component of bone?

a. Potassium
b. Phosphorus
c. Calcium
d. Hydroxide

A

a. Potassium

53
Q

Which type of bone composes the skull?

a. Long bones
b. Short bones
c. Flat bones
d. Pneumatic bone

A

c. Flat bones

54
Q

Which of the following are examples of fibrous joints?

a. Sutures
b. Pubic symphysis
c. Knee joint
d. Elbow

A

a. Sutures

55
Q

During total knee replacement surgery, which type of small, round knee bone would be replaced along with the ends of the long bones?

a. Flat bone
b. Sesamoid bone
c. Short bone
d. Irregular bone

A

b. Sesamoid bone

56
Q

Which is not the characteristic feature of the synovial joint that allows for free movement?

a. Presence of a capsule
b. Presence of fluid within the cavity
c. Presence of fibrous connective tissue
d. Presence of articulating cartilege

A

c. Presence of fibrous connective tissue

57
Q

How many chromatids and chromosomes should one expect to find in a secondary spermatocyte in a human?

a. 23 chromatids, 23 chromosomes
b. 46 chromatids, 46 chromosomes
c. 46 chromatids, 23 chromosomes
d. 92 chromatids, 46 chromosomes

A

c. 46 chromatids, 23 chromosomes

formed after meiosis I

58
Q

Which impairment in the male reproductive system will NOT necessarily lead to sterility?

a. Obstruction of bulbourethral glands
b. Blockage of the ampulla of vas deferens
c. Degeneration of epididymis
d. Prostatic cancer

A

a. Obstruction of bulbourethral glands

59
Q

What is spermiogenesis?

a. A process happening in the spermatic cord
b. The process of meiosis in males
c. Selection of spermatogonia to become sperm
d. Shedding of unnecessary cytoplasm

A

d. Shedding of unnecessary cytoplasm

60
Q

What would be a direct result of an enzymatic deficiency on the acrosome?

a. Implantation may occur in the uterine tube
b. Primary spermatocyte would not become secondary spermatocyte
c. Spermatid would not become primary spermatocyte
d. Egg would not complete metaphase II

A

d. Egg would not complete metaphase II

61
Q

Which hormonal supplementation therapy is the least likely to assist a female that has difficulties ovulating?

a. FSH
b. progesterone
c. estrogen
d. LH

A

b. progesterone

62
Q

Which structure is likely to be immediately affected due to spread of infection in the cervical canal?

A

a. Fallopian tube
b. Clitoris
c. Fimbriae
d. Fornix

63
Q

Which would NOT be a side effect of a drug that hypo-stimulates the Leydig cells on a pubertal human?

a. Increased GnRH secretion by hypothalamus
b. Increased FSH secretion by anterior pituitary
c. Decreased GnRH secretion by hypothalamus
d. Increased LH secretion by anterior pituitary

A

c. Decreased GnRH secretion by hypothalamus

64
Q

Which hormonal change is linked with the menses period of uterine cycle?

a. Increased levels of FSH and LH
b. Increased secretion of estrogen
c. Decreased levels of progesterone and estrogen
d. Increased secretion of progesterone by corpus luteum

A

c. Decreased levels of progesterone and estrogen

65
Q

Which hormone is consistently positively correlated with thickening of the endometrium?

a. Estrogen
b. LH
c. FSH
d. Progesterone

A

d. Progesterone

MCAT! (10 decks)

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