Unit XIV: Endocrinology and

Reproduction
1. Which of the following is expected to exhibit the greatest biological
activity?
A) Insulin like growth factor-1 free in the plasma
B) Cholecalciferol (vitamin D3)
C) Cortisol bound to corticosteroid binding globulin
D) T4 bound to thyroxine binding globulin
E) Aldosterone bound to plasma albumin
2. Which receptor controls nitric oxide (NO) release to cause
vasodilation during penile erection?
A) Leptin receptor
B) Angiotensin AT1 receptor
C) Endothelin ETA receptor
D) Muscarinic receptor
3. After menopause, hormone replacement therapy with estrogen-like
compounds is effective in preventing the progression of
osteoporosis. What is the mechanism of their protective effect?
A) They stimulate the activity of osteoblasts
B) They increase absorption of calcium from the gastrointestinal
tract
C) They stimulate calcium reabsorption by the renal tubules
D) They stimulate parathyroid hormone (PTH) secretion by the
parathyroid gland
4. Neurons that secrete antidiuretic hormone or oxytocin terminate in
which of the following structures?
A) Posterior pituitary
B) Median eminence
C) Mammillary body
D) Paraventricular nucleus
E) Supraoptic nucleus
5. Which of the following represents a physiological action of growth
hormone?
A) Increases the breakdown of muscle protein
 B) Increases utilization of glucose in muscle
C) Decreases storage of lipids in adipose cells
D) Decreases gene transcription
E) Decreases gluconeogenesis in the liver
6. Which hormones antagonize the effect of NO and cause the penis to
become flaccid after orgasm?
A) Endothelin and norepinephrine
B) Estrogen and progesterone
C) Luteinizing hormone (LH) and follicle-stimulating hormone
(FSH)
D) Progesterone and LH

Questions 7–9
 The red lines in the above figure illustrate the normal relationships
between plasma insulin concentration and glucose production in the liver
and between plasma insulin concentration and glucose uptake in muscle.
Use this figure to answer Questions 7–9.

7. Which lines most likely illustrate these relationships in a patient

with type 2 diabetes?
A) A and C
B) A and D
C) B and C
D) B and D
8. Which lines most likely illustrate these relationships in a patient
with acromegaly?
A) A and C
B) A and D
C) B and C
D) B and D
9. Line D most likely illustrates the influence of which of the
following?
A) Exercise
B) Obesity
C) Growth hormone (GH)
D) Cortisol
E) Glucagon
10. Thecal cells in the follicle are not able to produce what sex steroid?
A) Estradiol
B) Testosterone
C) Progesterone
D) Dihydrotestosterone
11. A baby is born with a penis, a scrotum with no testes, no vagina,
and XX chromosomes. This condition is referred to as
hermaphroditism. What could cause this abnormality?
A) Abnormally high levels of human chorionic gonadotropin
(hCG) production by the trophoblast cells
B) The presence of a testosterone-secreting tumor in the mother’s
right adrenal gland
C) Abnormally high levels of LH in the maternal blood
D) Abnormally low levels of testosterone in the maternal blood
E) Abnormally low rates of estrogen production by the placenta
12. Antidiuretic hormone (ADH) is increased by which of the
following?
A) A hyperosmotic extracellular fluid in the hypothalamus
B) A hyperosmotic extracellular fluid in the adenohypophysis
C) A hypoosmotic extracellular fluid in the hypothalamus
D) A hypoosmotic extracellular fluid in the adenohypophysis
E) A hypoosmotic fluid in the atria of the heart
13. In an individual with panhypopituitarism, which selection below
best describes the plasma hormone changes that would occur?
A) ↓GHRH, ↓somatostatin, ↓growth hormone, ↓somatomedin C
B) ↓GHRH, ↓somatostatin, ↓growth hormone, ↑somatomedin C
C) ↑GHRH, ↑somatostatin, ↑growth hormone, ↓somatomedin C
D) ↑GHRH, ↑somatostatin, ↓ growth hormone, ↓somatomedin C
E) ↑GHRH, ↓somatostatin, ↓growth hormone, ↓somatomedin C
14. Which of the following could inhibit the initiation of labor?
A) Administration of an antagonist of the actions of
progesterone
B) Administration of LH
C) Administration of an antagonist of PGE2 effects
D) Mechanically dilating and stimulating the cervix
E) Administration of oxytocin
15. A patient has nephrogenic diabetes insipidus. Which of the
following would either be expected or a suggested intervention?
A) Decreased plasma sodium concentration
B) Increased secretion of ADH from the supraoptic nuclei
C) High urine osmolality
D) Increased AVPR2 function
E) Decrease secretion of ADH from the supraoptic and
paraventricular nuclei
16. Which of the following would most likely cause a decrease in the
release of thyroid-stimulating hormone?
A) Decreased iodinase enzyme
B) Decreased iodine pump activity in thyroid gland
C) Decreased body temperature
D) Increased thyrotropin releasing hormone
E) Increased plasma thyroxine by venous infusion
17. The increased cardiac output caused by elevated circulating levels
of thyroid hormones is most likely caused by
A) Direct actions of thyroid-stimulating hormone on the heart
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B) Direct actions of thyroid-stimulating hormone on the brain
C) An increase in the metabolic demand of the tissues
D) An increase in plasma cholesterol and triglycerides
E) An increase in total body weight
18. If a radioimmunoassay is properly conducted and the amount of
radioactive hormone bound to antibody is low, what would this
result indicate?
A) Plasma levels of endogenous hormone are high
B) Plasma levels of endogenous hormone are low
C) More antibody is needed
D) Less radioactive hormone is needed
19. Which of the following depicts the most likely sequence of events
in an individual exposed to cold?
A) ↑Thyrotropin-releasing hormone, ↑thyroid-stimulating
hormone, ↑thyroxine
B) ↑Thyrotropin-releasing hormone, ↓thyroid-stimulating
hormone, ↑thyroxine
C) ↑Thyroid-stimulating hormone, ↑thyrotropin-releasing
hormone, ↑thyroxine
D) ↑Thyroid-stimulating hormone, ↓thyrotropin-releasing
hormone, ↑thyroxine
E) ↑Thyroxine, ↑thyrotropin-releasing hormone, ↑thyroid-
stimulating hormone
20. Spermatogenesis is regulated by a negative feedback control
system in which FSH stimulates the steps in sperm cell formation.
Which negative feedback signal associated with sperm cell
production inhibits pituitary formation of FSH?
A) Testosterone
B) Inhibin
C) Estrogen
D) LH
21. In an individual with a thyroid hormone producing adenoma, one
might expect which of the following?
A) ↑ T4, ↓ T3, ↓ TRH, ↓ TSH
B) ↑ T4, ↑ T3, ↓ TRH, ↓ TSH
C) ↑ T4, ↑ T3, ↑ TRH, ↓ TSH
D) ↑ T4, ↑ T3, ↓ TRH, ↑ TSH
E) ↓ T4, ↑ T3, ↓ TRH, ↓ TSH
 22. When do progesterone levels rise to their highest point during the
female hormonal cycle?
A) Between ovulation and the beginning of menstruation
B) Immediately before ovulation
C) When the blood concentration of LH is at its highest point
D) When 12 primary follicles are developing to the antral stage
23. You suspect thyroid disease in a female patient. Based on the
plasma values below, which of the following would be expected?

[TSH] Total [T4] [TBG]

Normal range 0.4-5.5 mU/l 5.6-14.7 µg/dl 1.7-3.6 µg/dl

Patient data 9.3 2.3 3.0

A) Graves’ disease
B) Secondary hyperthyroidism
C) Hashimoto’s disease
D) Secondary hypothyroidism
E) Euthyroid pregnant
24. Which of the following enzymes catalyzes the conversion of
cholesterol to pregnenolone?
A) Aldosterone synthase
B) Lipoprotein lipase
C) Hormone sensitive lipase
D) 11β-Hydroxylase
E) Cholesterol desmolase
25. Which of the following would most likely occur if plasma
aldosterone levels were low?
A) Hyperkalemia
B) Hypokalemia
C) Hypernatremia
D) Hypertension
26. A professional athlete in her mid-20s has not had a menstrual
cycle for 5 years, although a bone density scan revealed normal
skeletal mineralization. Which fact may explain these
observations?
A) She consumes a high-carbohydrate diet
B) Her grandmother sustained a hip fracture at age 79 years
 C) Her blood pressure is higher than normal
D) Her plasma estrogen concentration is very low
E) She has been taking anabolic steroid supplements for 5 years
27. During a chronic infusion of aldosterone in an experimental
animal model, one would expect which of the following?
A) ↑Blood pressure, ↔extracellular fluid volume, ↓urinary
sodium excretion
B) ↑Blood pressure, ↓extracellular fluid volume, ↔urinary
sodium excretion
C) ↑Blood pressure, ↔extracellular fluid volume, ↑urinary
sodium excretion
D) ↑Blood pressure, ↑extracellular fluid volume, ↔urinary
sodium excretion
E) ↑Blood pressure, ↔extracellular fluid volume, ↔urinary
sodium excretion
28. In the circulatory system of a fetus, which of the following is
greater before birth than after birth?
A) Arterial Po2
B) Right atrial pressure
C) Aortic pressure
D) Left ventricular pressure
29. In response to a physiological stimulus such as the stress of taking
an important quiz, which of the following reflects the most likely
sequence of events?
A) ↑Cortisol, ↑corticotropin, ↑corticotropin-releasing hormone
B) ↑Corticotropin-releasing hormone, ↑corticotropin, ↑cortisol
C) ↑Cortisol, ↓corticotropin, ↑corticotropin-releasing hormone
D) ↑Corticotropin-Releasing hormone, ↑corticotropin, ↓cortisol
E) ↑Cortisol, ↑corticotropin, ↓corticotropin-releasing hormone
30. Which of the following best characterizes the metabolic actions of
cortisol?
A) ↑Muscle glucose uptake, ↑muscle amino acid uptake,
↑adipose tissue fat uptake
B) ↑Muscle glucose uptake, ↓muscle amino acid uptake, ↑adipose
tissue fat uptake
C) ↓Muscle glucose uptake, ↓muscle amino acid uptake,
↑adipose tissue fat uptake
D) ↓Muscle glucose uptake, ↑muscle amino acid uptake,
↓adipose tissue fat uptake
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E) ↓Muscle glucose uptake, ↓muscle amino acid uptake, ↓adipose
tissue fat uptake
31. Which of the following is most likely to occur as a result of chronic
hyperglycemia associated with untreated type 1 diabetes mellitus?
A) Increased intracellular fluid volume
B) Decreased urinary glucose
C) Metabolic alkalosis
D) Osmotic diuresis and polyuria
E) Improved eyesight
32. Which enzyme in the cytochrome P450 steroid synthesis cascade is
directly responsible for estradiol synthesis?
A) 17-Beta-hydroxysteroid dehydrogenase
B) 5-Alpha reductase
C) Aromatase
D) Side chain cleavage enzyme
33. Which of the following is greater after birth than before birth?
A) Flow through the foramen ovale
B) Pressure in the right atrium
C) Flow through the ductus arteriosus
D) Aortic pressure
34. Immediately after consuming a meal consisting of a large burger,
French fries, onion rings, and a diet cola, one might expect a
DECREASE in which of following?
A) Amino acid transport into cells
B) Fa y acid synthesis
C) Hormone sensitive lipase
D) Liver glycogen
E) Cell permeability to glucose
35. In an individual with untreated insulin dependent diabetes
mellitus (type 1), one would expect which of the following?
A) ↑Plasma free fa y acids, ↓liver glycogen, ↑skeletal muscle
mass
B) ↑Plasma free fa y acids, ↓liver glycogen, ↓skeletal muscle
mass
C) ↑Plasma free fa y acids, ↑liver glycogen, ↓skeletal muscle
mass
D) ↓Plasma free fa y acids, ↓liver glycogen, ↑skeletal muscle
mass
 E) ↓Plasma free fa y acids, ↑liver glycogen, ↓skeletal muscle
mass
36. Which of the following changes would be expected to help
maintain plasma glucose in the postabsorptive?
A) ↓Insulin, ↑glucagon, ↓growth hormone, ↓cortisol
B) ↓Insulin, ↑glucagon, ↑growth hormone, ↓cortisol
C) ↓Insulin, ↑glucagon, ↑growth hormone, ↑cortisol
D) ↑Insulin, ↓glucagon, ↓growth hormone, ↑cortisol
E) ↑Insulin, ↓glucagon, ↑growth hormone, ↑cortisol
37. For male differentiation to occur during embryonic development,
testosterone must be secreted from the testes. What stimulates the
secretion of testosterone during embryonic development?
A) LH from the maternal pituitary gland
B) hCG
C) Inhibin from the corpus luteum
D) GnRH from the embryo’s hypothalamus
38. Which of the following best describes insulin?
A) Lipid-soluble hormone tightly bound to plasma proteins
B) Peptide hormone that activates an intracellular receptor
C) Peptide hormone that activates a G-coupled protein receptor
D) Peptide hormone that activates an enzyme-linked receptor
E) Steroid hormone that activates an enzyme-linked receptor
39. If one were to experience a sudden decrease in extracellular fluid
calcium, which of the following would most likely be the first
physiological response to buffer the change in calcium?
A) Increased calcium absorption in the gut
B) Decreased phosphate absorption in the gut
C) Increased parathyroid hormone from the anterior pituitary
D) Decreased renal excretion of phosphate
E) Increased exchange of calcium with the bone fluid
40. As menstruation ends, estrogen levels in the blood rise rapidly.
What is the source of the estrogen?
A) Corpus luteum
B) Developing follicles
C) Endometrium
D) Stromal cells of the ovaries
E) Anterior pituitary gland
41. A 30-year-old woman reports to the clinic for a routine physical
examination. The examination reveals she is pregnant. Her plasma
 p g p
levels of TSH are high, but her total thyroid hormone concentration
is normal. Which of the following best reflects the patient’s clinical
state?
A) Graves’ disease
B) Hashimoto’s disease
C) A pituitary tumor secreting TSH
D) A hypothalamic tumor secreting thyrotropin-releasing
hormone (TRH)
E) The patient is taking thyroid extract
42. Which of the following would be expected in a patient with
chronic renal failure?

Plasma[1,25-(OH)2D] Plasma [PTH] Bone Resorption

A) ↑ ↑ ↑

B) ↑ ↑ ↓

C) ↑ ↓ ↓

D) ↓ ↓ ↑

E) ↓ ↑ ↓

F) ↓ ↑ ↑

43. A female athlete who took testosterone-like steroids for several

months stopped having normal menstrual cycles. What is the best
explanation for this observation?
A) Testosterone stimulates inhibin production from the corpus
luteum
B) Testosterone binds to receptors in the endometrium, resulting
in the failure of the endometrium to develop during the
normal cycle
C) Testosterone binds to receptors in the anterior pituitary that
stimulate the secretion of FSH and LH
D) Testosterone inhibits the hypothalamic secretion of GnRH
and the pituitary secretion of LH and FSH
 44. An experiment is conducted in which ADH is administered at
hour 3 to four subjects (A to D). In the above figure, which lines
most likely reflect the response to ADH administration in a normal
patient and in a patient with central diabetes insipidus?

Normal Central Diabetes Insipidus

A) B A

B) B D

C) D A

D) D B

45. Which of the following decreases the resistance in the arteries

leading to the sinuses of the penis?
A) Stimulation of the sympathetic nerves innervating the arteries
B) NO
C) Inhibition of activity of the parasympathetic nerves leading to
the arteries
D) All the above
46. Using the three following statements, select the best answer.
1. Hydroxyapatite is the major crystalline salt in calcified bone
2. An osteon is made up of concentric layers of bone called
lamellae
3. Osteocytes are the major cells responsible for the formation of
new bone tissue
A) Only statement 1 is correct
B) Statement 1 and 2 are correct
C) Statements 1 and 3 are correct
D) All statements are correct
E) No statements are correct
47. All of the following statements about parathyroid hormone are
true EXCEPT one. Which one is the EXCEPTION?
A) PTH directly activates osteoblasts and osteocytes
B) PTH inhibits the production of vitamin D hormones
C) PTH promotes bone resorption in response to decreased
plasma calcium
D) PTH promotes the movement of calcium from bone fluid to
the extracellular fluid
E) PTH promotes calcium reabsorption in the renal distal tubule
and collecting duct
48. A 46-year-old man has “puffy” skin and is lethargic. His plasma
TSH concentration is low and increases markedly when he is given
TRH. What is the most likely diagnosis?
A) Hyperthyroidism due to a thyroid tumor
B) Hyperthyroidism due to an abnormality in the hypothalamus
C) Hypothyroidism due to an abnormality in the thyroid
D) Hypothyroidism due to an abnormality in the hypothalamus
E) Hypothyroidism due to an abnormality in the pituitary
49. Negative feedback on FSH release from the anterior pituitary in
men that results in a reduction in estradiol production is due to
which hormone?
A) Progesterone
B) Estradiol
C) Testosterone
D) Inhibin
50. During the first few years after menopause, FSH levels are
normally extremely high. A 56-year-old woman completed
 menopause 3 years ago. However, she is found to have low levels
of FSH in her blood. What is the best explanation for this finding?
A) She has been receiving hormone replacement therapy with
estrogen and progesterone since she completed menopause
B) Her adrenal glands continue to produce estrogen
C) Her ovaries continue to secrete estrogen
D) She took birth control pills for 20 years before menopause
51. Blockade of what receptors will prolong erection in a man?
A) Estrogen receptors
B) Cholesterol receptors
C) Muscarinic receptors
D) Phosphodiesterase-5 receptors
52. Which of the following pairs of hormones and the corresponding
action is incorrect?
A) Glucagon—increased glycogenolysis in liver
B) Glucagon—increased glycogenolysis in skeletal muscle
C) Glucagon—increased gluconeogenesis
D) Cortisol—increased gluconeogenesis
E) Cortisol—decreased glucose uptake in muscle
53. A large dose of insulin is administered intravenously to a patient.
Which set of hormonal changes is most likely to occur in the
plasma in response to the insulin injection?

Growth Hormone Glucagon Epinephrine

A) ↑ ↓ ↔

B) ↔ ↑ ↑

C) ↑ ↑ ↑

D) ↓ ↑ ↑

E) ↓ ↓ ↔

54. What is a frequent cause of delayed breathing at birth?

A) Fetal hypoxia during the birth process
B) Maternal hypoxia during the birth process
C) Fetal hypercapnia
D) Maternal hypercapnia
55. Which hormone is largely unbound to plasma proteins?
A) Cortisol
 B) T4
C) ADH
D) Estradiol
E) Progesterone
56. What is the mechanism by which the zona pellucida becomes
“hardened” after penetration of a sperm cell to prevent a second
sperm from penetrating?
A) A reduction in estradiol
B) The proteins released from the acrosome of the sperm
C) An increase in intracellular calcium in the oocyte
D) An increase in testosterone that affects the sperm
57. Why is milk produced by a woman only after delivery, not before?
A) Levels of LH and FSH are too low during pregnancy to
support milk production
B) High levels of progesterone and estrogen during pregnancy
suppress milk production
C) The alveolar cells of the breast do not reach maturity until
after delivery
D) High levels of oxytocin are required for milk production to
begin, and oxytocin is not secreted until the baby stimulates
the nipple
58. Which of the following increases the rate of excretion of calcium
ions by the kidney?
A) A decrease in calcitonin concentration in the plasma
B) An increase in phosphate ion concentration in the plasma
C) A decrease in the plasma level of PTH
D) Metabolic alkalosis
59. A patient has hyperthyroidism due to a pituitary tumor. Which set
of physiological changes would be expected?

Thyroglobulin Synthesis Heart Rate Exophthalmos

A) ↑ ↑ +

B) ↑ ↑ −

C) ↑ ↓ +

D) ↓ ↓ +

E) ↓ ↓ −

F) ↓ ↑ −
 60. A 25-year-old man is severely injured when hit by a speeding
vehicle and loses 20% of his blood volume. Which set of
physiological changes would be expected to occur in response to
the hemorrhage?

Atrial Stretch Receptor Activity Arterial Baroreceptor Activity ADH Secretion

A) ↓ ↓ ↑

B) ↓ ↓ ↓

C) ↔ ↑ ↑

D) ↑ ↑ ↑

E) ↑ ↑ ↓

61. If a woman has a tumor that is secreting large amounts of estrogen

from the adrenal gland, which of the following will occur?
A) Progesterone levels in the blood will be very low
B) Her LH secretion rate will be totally suppressed
C) She will not have normal menstrual cycles
D) Her bones will be normally calcified
E) All the above
62. When compared with the postabsorptive state, which set of
metabolic changes would most likely occur during the
postprandial state?

Hepatic Glucose Uptake Muscle Glucose Uptake Hormone-Sensitive Lipase Activity

A) ↑ ↑ ↑

B) ↑ ↓ ↑

C) ↓ ↑ ↓

D) ↑ ↑ ↓

E) ↓ ↑ ↑

63. Very early in embryonic development, testosterone is formed

within male embryos. What is the function of this hormone at this
stage of development?
A) Stimulation of bone growth
B) Stimulation of development of male sex organs
C) Stimulation of development of skeletal muscle
 D) Inhibition of LH secretion
64. During spermatogenesis, estrogen is produced by
A) Leydig cells in response to FSH
B) Sertoli cells in response to FSH
C) Leydig cells in response to LH
D) Sertoli cells in response to LH
65. A patient arrives in the emergency department apparently in
cardiogenic shock due to a massive heart a ack. His initial arterial
blood sample reveals the following concentrations of ions and pH
level:

Sodium 137 mmol/l

Bicarbonate 14 mmol/l

Free calcium 2.8 mmol/l

Potassium 4.8 mmol/l

pH 7.16

To correct the acidosis, the a ending physician begins an infusion of

sodium bicarbonate and after 1 hour obtains another blood sample, which
reveals the following values:

Sodium 138 mmol/l

Bicarbonate 22 mmol/l

Free calcium 2.3 mmol/l

Potassium 4.5 mmol/l

pH 7.34

What is the cause of the decrease in calcium ion concentration?

A) The increase in arterial pH resulting from the sodium
bicarbonate infusion inhibited PTH secretion
B) The increase in pH resulted in the stimulation of osteoblasts,
which removed calcium from the circulation
C) The increase in pH resulted in an elevation in the concentration
of HPO4 −, which shifted the equilibrium between HPO4 − and
Ca2+ toward CaHPO4
D) The increase in arterial pH stimulated the formation of 1,25-
dihydroxycholecalciferol, which resulted in an increased rate of
 absorption of calcium from the gastrointestinal tract
66. The prostate fluid contributes the bulk of the volume of semen,
which includes
A) Calcium, citrate, phosphate, and profibrinolysin
B) Fructose, citric acid, prostaglandins, and fibrinogen
C) Sex hormones
D) Mucus
67. A 30-year-old woman is breastfeeding her infant. During suckling,
which hormonal response is expected in the woman?
A) Increased secretion of ADH from the supraoptic nuclei
B) Increased secretion of ADH from the paraventricular nuclei
C) Increased secretion of oxytocin from the paraventricular
nuclei
D) Decreased secretion of neurophysin
E) Increased plasma levels of both oxytocin and ADH
68. A 30-year-old man has Conn’s syndrome. Which set of
physiological changes is most likely to occur in this patient
compared with a healthy person?

Arterial Pressure Extracellular Fluid Volume Sodium Excretion

A) ↔ ↔ ↔

B) ↑ ↔ ↔

C) ↑ ↑ ↔

D) ↔ ↑ ↓

E) ↑ ↑ ↓

69. Which of the following is important in the process of capacitation

of sperm after ejaculation?
A) Microtubule reorganization
B) Increased testosterone secretion by spermatozoa
C) Washout of inhibitory factors
D) Influx of glucose
70. Dehydroepiandrosterone sulfate (DHEAS), the precursor for the
high levels of estradiol that occur in pregnancy, is made in what
tissue?
A) Fetal adrenal gland
B) Ovary of the mother
 C) Placenta
D) Adrenal gland of the mother
71. What is the consequence of sporadic nursing of the neonate by the
mother?
A) An increase in prolactin-releasing hormone
B) An increase in oxytocin
C) Lack of birth control
D) Lack of prolactin surge
72. Which of the following would be associated with parallel changes
in aldosterone and cortisol secretion?
A) Addison’s disease
B) Cushing’s disease
C) Cushing’s syndrome (adrenal tumor)
D) A low-sodium diet
E) Administration of a converting enzyme inhibitor
73. The process of spermatogenesis begins with spermatogonia and
results in which of the following?
A) 1 diploid spermatid
B) 4 diploid spermatids
C) 1 haploid spermatid
D) 2 haploid spermatids
E) 4 haploid spermatids
74. RU486 causes abortion if it is administered before or soon after
implantation. What is the specific effect of RU486?
A) It binds to LH receptors, stimulating the secretion of
progesterone from the corpus luteum
B) It blocks progesterone receptors so that progesterone has no
effect within the body
C) It blocks the secretion of FSH by the pituitary
D) It blocks the effects of oxytocin receptors in the uterine
muscle
75. A 55-year-old man has developed the syndrome of inappropriate
antidiuretic hormone secretion due to carcinoma of the lung.
Which physiological response would be expected?
A) Increased plasma osmolality
B) Inappropriately low urine osmolality (relative to plasma
osmolality)
C) Increased thirst
D) Decreased secretion of ADH from the pituitary gland
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76. During pregnancy, the uterine smooth muscle is quiescent. During
the ninth month of gestation, the uterine muscle becomes
progressively more excitable. What factor contributes to the
increase in excitability?
A) Placental estrogen synthesis rises to high rates
B) Progesterone synthesis by the placenta decreases
C) Uterine blood flow reaches its highest rate
D) PGE2 synthesis by the placenta decreases
E) Activity of the fetus falls to low levels
77. A 20-year-old woman is not having menstrual cycles. Her plasma
progesterone concentration is found to be minimal. What is the
explanation for the low level of progesterone?
A) LH secretion rate is elevated
B) LH secretion rate is suppressed
C) FSH secretion rate is suppressed
D) No corpus luteum is present
E) High inhibin concentration in the plasma has suppressed
progesterone synthesis
78. Before the preovulatory surge in LH, granulosa cells of the follicle
secrete which hormone?
A) Testosterone
B) Progesterone
C) Estrogen
D) Inhibin

Questions 79 and 80
 79. Based on the above figure, which set of curves most likely reflects
the responses in a healthy individual and in patients with type 1 or
type 2 diabetes mellitus (Diabetes mellitus)?

Healthy Type 1 Diabetes mellitus Type 2 Diabetes mellitus

A) 3 2 1

B) 1 2 3

C) 1 3 2

D) 2 1 3

E) 2 3 1

80. Based on the above figure, which set of curves most likely reflects
the responses in a healthy person and in a patient in the early
stages of Cushing’s syndrome?
 Healthy Cushing’s Syndrome
A) 3 2

B) 1 2

C) 1 3

D) 2 1

E) 2 3

81. Which hormone activates enzyme-linked receptors?

A) ADH
B) Insulin
C) ACTH
D) PTH
E) Aldosterone
82. Which of the following is produced by the trophoblast cells during
the first 3 weeks of pregnancy?
A) Estrogen
B) LH
C) Oxytocin
D) hCG
E) None of the above
83. Which of the following is higher in a neonate than in a fetus?
A) Flow through the foramen ovale
B) Right atrial pressure
C) Flow through the ductus arteriosus
D) Aortic pressure
84. Which finding is most likely in a patient who has myxedema?
A) Somnolence
B) Palpitations
C) Increased respiratory rate
D) Increased cardiac output
E) Weight loss
85. At birth, a large, well-nourished baby is found to have a plasma
glucose concentration of 17 mg/dl (normal is 80 to 100 mg/dl) and a
plasma insulin concentration twice the normal value. What is the
explanation for these findings?
A) The neonate experienced in utero malnutrition
B) The mother was malnourished during pregnancy
 C) The mother has diabetes, with poorly controlled
hyperglycemia
D) The mother is obese
86. Degradation of the corpus luteum is prevented by which of the
following?
A) Increased estrogen secretion by the developing placenta
B) Release of hCG from the trophoblasts
C) Forward positive regulation by LH
D) Placental derived prolactin
87. Which of the following stimulates the secretion of PTH?
A) An increase in extracellular calcium ion activity above the
normal value
B) An increase in calcitonin concentration
C) Respiratory acidosis
D) Increased secretion of PTH-releasing hormone from the
hypothalamus
E) None of the above
88. A 40-year-old woman consumes a high-potassium diet for several
weeks. Which hormonal change is most likely to occur?
A) Increased secretion of DHEA
B) Increased secretion of cortisol
C) Increased secretion of aldosterone
D) Increased secretion of ACTH
E) Decreased secretion of CRH
89. After implantation into the uterus, nutrition of the blastocyst
comes from which structure?
A) Placenta
B) Decidua
C) Glomerulosa cells
D) Corpus luteum
90. Which hormone is not stored in its endocrine-producing gland?
A) T4
B) PTH
C) Aldosterone
D) ACTH
E) Insulin
91. A young woman comes to the emergency department with a
vertebral compression fracture. Radiographs of the spine indicate
 generalized demineralization. She is vegetarian, does not smoke or
drink alcohol, and has a normal plasma potassium concentration of
5.4 mEq/l, a sodium concentration of 136 mEq/l, and a plasma
calcium concentration of 7.0 mg/dl. Her vitamin D3 value is several
times greater than normal, although her 1,25-
dihydroxycholecalciferol concentration is at the lower limit of
detectability. She has been in renal failure for the past 5 years and
undergoes hemodialysis three times each week. What is the cause
of her low 1,25-dihydroxycholecalciferol level?
A) Metabolic acidosis
B) Metabolic alkalosis
C) She is unable to form 1,25-dihydroxycholecalciferol because
of her extensive kidney disease
D) She is undergoing dialysis with a dialysis fluid that does not
contain calcium
E) She is taking receiving calcium supplements
92. A placenta is incapable of synthesizing which hormones?
A) Estrogen
B) Progesterone
C) Androgens
D) Estriol
93. Which of the following hormones is most closely associated with
the secretory phase of the endometrial cycle?
A) Progesterone
B) Estrogen
C) FSH
D) LH
E) Inhibin
94. Which finding would likely be reported in a patient with a
deficiency in iodine intake?
A) Weight loss
B) Nervousness
C) Increased sweating
D) Increased synthesis of thyroglobulin
E) Tachycardia
95. A 37-year-old woman presents to her physician with an enlarged
thyroid gland and high plasma levels of T4 and T3. Which of the
following is likely to be decreased?
 A) Heart rate
B) Cardiac output
C) Peripheral vascular resistance
D) Ventilation rate
E) Metabolic rate
96. Before intercourse, a woman irrigates her vagina with a solution
that lowers the pH of the vaginal fluid to 4.5. What will be the
effect on sperm cells in the vagina?
A) The metabolic rate will increase
B) The rate of movement will decrease
C) The formation of PGE2 will increase
D) The rate of oxygen consumption will increase
97. Which hormonal responses would be expected after a meal high in
protein?

Insulin Glucagon Growth Hormone

A) ↑ ↑ ↓

B) ↑ ↑ ↑

C) ↑ ↓ ↓

D) ↓ ↓ ↑

E) ↓ ↑ ↑

98. Men who take large doses of testosterone-like androgenic steroids

for long periods are sterile in the reproductive sense of the word.
What is the explanation for this finding?
A) High levels of androgens bind to testosterone receptors in the
Sertoli cells, resulting in overstimulation of inhibin formation
B) Overstimulation of sperm cell production results in the
formation of defective sperm cells
C) High levels of androgen compounds inhibit the secretion of
GnRH by the hypothalamus, resulting in the inhibition of LH
and FSH release by the anterior pituitary
D) High levels of androgen compounds produce hypertrophic
dysfunction of the prostate gland
99. Cortisone is administered to a 30-year-old woman for the
treatment of an autoimmune disease. Which of the following is
most likely to occur?
 A) Increased ACTH secretion
B) Increased cortisol secretion
C) Increased insulin secretion
D) Increased muscle mass
E) Hypoglycemia between meals
100. In the hypothalamic-pituitary-gonadal axis of the female, what is
the follicular cell type that produces inhibin?
A) Cytotrophoblasts
B) Synthiotrophoblasts
C) Granulosa
D) Thecal
101. The function of which of the following is increased by an elevated
parathyroid hormone concentration?
A) Osteoclasts
B) Hepatic formation of 25-hydroxycholecalciferol
C) Phosphate reabsorptive pathways in the renal tubules
D) All the above
102. Which statement about peptide or protein hormones is usually
true?
A) They have longer half-lives than steroid hormones
B) They have receptors on the cell membrane
C) They have a slower onset of action than both steroid and
thyroid hormones
D) They are not stored in endocrine-producing glands
103. Which set of physiological changes would be most likely to occur
in a patient with acromegaly?

Pituitary Mass Kidney Mass Femur Length

A) ↓ ↓ ↑

B) ↓ ↑ ↑

C) ↑ ↔ ↔

D) ↑ ↑ ↔

E) ↑ ↑ ↑

104. Cortisol and GH are most dissimilar in their metabolic effects on

which of the following?
A) Protein synthesis in muscle
 B) Glucose uptake in peripheral tissues
C) Plasma glucose concentration
D) Mobilization of triglycerides
105. Why do infants of mothers who had adequate nutrition during
pregnancy not require iron supplements or a diet rich in iron until
about 3 months of age?
A) Growth of the infant does not require iron until after the third
month
B) The fetal liver stores enough iron to meet the infant’s needs
until the third month
C) Synthesis of new red blood cells begins after 3 months
D) Muscle cells that develop before the third month do not
contain myoglobin
106. Cortisone is administered to a patient for the treatment of an
autoimmune disease. Which of the following would least likely
occur in response to the cortisone treatment?
A) Hypertrophy of the adrenal glands
B) Increased plasma levels of C-peptide
C) Decreased CRH secretion
D) Increased blood pressure
E) Hyperglycemia
107. All of the following accurately describe the regulation of the
female sexual cycle EXCEPT one. Which one is the EXCEPTION?
A) Estradiol inhibits GnRH release during the post ovulatory
phase
B) Progesterone increases GnRH release during the post
ovulatory phase
C) Estradiol increases LH in the days immediately preceding
ovulation
D) Falling progesterone and estrogen late in the luteal phase
allows LH and FSH to rise
E) LH and FSH increase estradiol release during the follicular
phase
108. If a male is born without a penis and testes, a defect is likely in
which gene on the Y chromosome?
A) ERE—estrogen response element
B) ARE—androgen response element
C) SRY—affecting Sertoli cells
D) ERG—early response genes
 y p g
109. Where does fertilization normally take place?
A) Uterus
B) Cervix
C) Ovary
D) Ampulla of the fallopian tubes
110. Which finding is most likely to occur in a patient who has
uncontrolled type 1 diabetes mellitus?
A) Decreased plasma osmolality
B) Increased plasma volume
C) Increased plasma pH
D) Increased release of glucose from the liver
E) Decreased rate of lipolysis
111. GH secretion would most likely be suppressed under which
condition?
A) Acromegaly
B) Gigantism
C) Deep sleep
D) Exercise
E) Acute hyperglycemia
112. Pregnenolone is not in the biosynthetic pathway of which
substance?
A) Cortisol
B) Estrogen
C) Aldosterone
D) 1,25(OH)2D
E) DHEA
113. Two days before the onset of menstruation, secretions of FSH and
LH reach their lowest levels. What is the cause of this low level of
secretion?
A) The anterior pituitary gland becomes unresponsive to the
stimulatory effect of GnRH
B) Estrogen from the developing follicles exerts a feedback
inhibition on the hypothalamus
C) The rise in body temperature inhibits hypothalamic release of
GnRH
D) Secretion of estrogen, progesterone, and inhibin by the corpus
luteum suppresses hypothalamic secretion of GnRH and
pituitary secretion of FSH
114. Which condition contributes to “sodium escape” in persons with
Conn’s syndrome?
A) Decreased plasma levels of atrial natriuretic peptide
B) Increased plasma levels of angiotensin II
C) Decreased sodium reabsorption in the collecting tubules
D) Increased arterial pressure
115. Which of the following most accurately describes events in the
female sexual cycle?
A) FSH causes the development of the corpus luteum
B) Estrogen and LH have a positive feedback relationship during
the late follicular phase
C) Estrogens are primarily produced by theca cells in the
developing ovary
D) During the luteal phase, estrogen increases to a greater degree
than progesterone
E) LH is most responsible for the development of primary
follicles
116. A 30-year-old woman reports to the clinic for a routine physical
examination, which reveals she is pregnant. Her plasma levels of
TSH are high, but her total T4 concentration (protein bound and
free) is normal. Which of the following best reflects this patient’s
clinical state?
A) Graves’ disease
B) Hashimoto’s disease
C) A pituitary tumor that is secreting TSH
D) A hypothalamic tumor that is secreting TRH
E) The patient is taking thyroid extract
117. A man has a disease that destroyed only the motor neurons of the
spinal cord below the thoracic region. Which aspect of sexual
function would not be possible?
A) Arousal
B) Erection
C) Lubrication
D) Ejaculation
118. Which of the following is responsible for invasion of the uterus
and formation of the placenta?
A) Trophoblasts
B) Oocyte
 C) Decidua
D) Endometrium
119. A sustained program of lifting heavy weights will increase bone
mass. What is the mechanism of this effect of weightlifting?
A) Elevated metabolic activity stimulates parathyroid hormone
secretion
B) Mechanical stress on the bones increases the activity of
osteoblasts
C) Elevated metabolic activity results in an increase in dietary
calcium intake
D) Elevated metabolic activity results in stimulation of calcitonin
secretion
120. The hormone most responsible for maintaining milk production
after parturition is
A) Estrogen
B) Progesterone
C) Oxytocin
D) Prolactin
E) Inhibin
121. Which of the following would be expected in a patient with a
genetic deficiency of 11-β-hydroxysteroid dehydrogenase type II?
A) Hyperkalemia
B) Hypertension
C) Increased plasma renin activity
D) Increased plasma [aldosterone]
E) Hyperglycemia
122. Which physiological response is greater for T3 than for T4?
A) Secretion rate from the thyroid
B) Plasma concentration
C) Plasma half-life
D) Affinity for nuclear receptors in target tissues
E) Latent period for the onset of action in target tissues
123. A “birth control” compound for men has been sought for several
decades. Which substance would provide effective sterility?
A) A substance that mimics the actions of LH
B) A substance that blocks the actions of inhibin
C) A substance that blocks the actions of FSH
D) A substance that mimics the actions of GnRH
 124. For milk to flow from the nipple of the mother into the mouth of
the nursing infant, what must occur?
A) Myoepithelial cells must relax
B) Prolactin levels must fall
C) Oxytocin secretion from the posterior pituitary must take
place
D) The baby’s mouth must develop a strong negative pressure
over the nipple
E) All the above
125. A number of normal physiological changes occur during
pregnancy. Which of the following best describes one of these
changes in the mother?
A) Increase total peripheral resistance
B) Increased cardiac output
C) Decreased metabolic rate
D) Decreased body weight
E) Decreased uterine size
126. Which set of physiological changes would be expected in a
nondiabetic patient with Cushing’s disease?

Plasma Aldosterone Plasma Cortisol Plasma Insulin

A) ↑ ↑ ↑

B) ↑ ↑ ↔

C) ↑ ↔ ↔

D) ↔ ↔ ↑

E) ↔ ↑ ↔

F) ↔ ↑ ↑

127. When compared with the late-evening values typically observed

in normal subjects, plasma levels of both ACTH and cortisol would
be expected to be higher in which persons?
A) Normal subjects after waking in the morning
B) Normal subjects who have taken dexamethasone
C) Patients with Cushing’s syndrome (adrenal adenoma)
D) Patients with Addison’s disease
E) Patients with Conn’s syndrome
 128. Which of the following conditions or hormones would most
likely increase GH secretion?
A) Hyperglycemia
B) Exercise
C) Somatomedin
D) Somatostatin
E) Aging
129. Which set of findings would be expected in a person maintained
on a long-term low-sodium diet?

Plasma [Aldosterone] Plasma [Atrial Natriuretic Peptide] Plasma [Cortisol]

A) ↑ ↑ ↔

B) ↑ ↓ ↓

C) ↑ ↓ ↔

D) ↔ ↔ ↔

E) ↓ ↓ ↓

F) ↓ ↑ ↓

130. What would be associated with parallel changes in aldosterone

and cortisol secretion?
A) Addison’s disease
B) Cushing’s disease
C) Cushing’s syndrome (ectopic ACTH-producing tumor)
D) A high-sodium diet
E) Administration of a converting enzyme inhibitor
131. Which blood vessel in the fetus has the highest PO 2?
A) Ductus arteriosus
B) Ductus venosus
C) Ascending aorta
D) Left atrium
132. A 59-year-old woman has osteoporosis, hypertension, hirsutism,
and hyperpigmentation. Magnetic resonance imaging indicates
that the pituitary gland is not enlarged. Which condition is most
consistent with these findings?
A) Pituitary ACTH-secreting tumor
B) Ectopic ACTH-secreting tumor
C) Inappropriately high secretion rate of CRH
 D) Adrenal adenoma
E) Addison’s disease
133. Which set of findings is an inappropriate hypophysial hormone
response to the hypothalamic hormone listed?

Hypothalamic Hormone Secretion Hypophysial Hormone

A) Somatostatin ↓ GH

B) Dopamine ↑ Prolactin

C) GnRH ↑ LH

D) TRH ↑ TSH

E) CRH ↑ ACTH

134. A patient is administered sufficient T4 to increase plasma levels of

the hormone several fold. Which set of changes is most likely in
this patient after several weeks of T4 administration?

Respiratory Rate Heart Rate Plasma Cholesterol Concentration

A) ↑ ↑ ↑

B) ↑ ↑ ↓

C) ↑ ↓ ↑

D) ↓ ↓ ↑

E) ↓ ↑ ↓

135. Which of the following hormones is most critical for sustaining a

successful pregnancy, even up through week 12 of gestation?
A) Estrogen
B) Progesterone
C) hCG
D) GnRH
E) Inhibin
136. What causes menopause?
A) Reduced levels of gonadotropic hormones secreted from the
anterior pituitary gland
B) Reduced responsiveness of the follicles to the stimulatory
effects of gonadotropic hormones
 C) Reduced rate of secretion of progesterone from the corpus
luteum
D) Reduced numbers of follicles available in the ovary for
stimulation by gonadotropic hormones
137. What does not increase when insulin binds to its receptor?
A) Fat synthesis in adipose tissue
B) Protein synthesis in muscle
C) Glycogen synthesis
D) Gluconeogenesis in the liver
E) Intracellular tyrosine kinase activity
138. Release of which hormone is an example of neuroendocrine
secretion?
F) GH
G) Cortisol
H) Oxytocin
I) Prolactin
J) ACTH
139. The ability of a fetus to effectively use the relatively low maternal
Po2 is facilitated by which of the following?
A) Decreased glucose transport in the placental villi
B) Increased production of amniotic fluid
C) Increased total fetal hemoglobin concentration
D) Decreased placental membrane permeability
E) Decreased fetal hemoglobin binding capacity
140. Inhibition of the iodide pump would be expected to cause which
change?
A) Increased synthesis of T4
B) Increased synthesis of thyroglobulin
C) Increased metabolic rate
D) Decreased TSH secretion
E) Extreme nervousness
141. Before implantation, the blastocyst obtains its nutrition from
uterine endometrial secretions. How does the blastocyst obtain
nutrition during the first week after implantation?
A) It continues to derive nutrition from endometrial secretions
B) The cells of the blastocyst contain stored nutrients that are
metabolized for nutritional support
C) The placenta provides nutrition derived from maternal blood
 D) The trophoblast cells digest the nutrient-rich endometrial cells
and then absorb their contents for use by the blastocyst
142. Which pituitary hormone has a chemical structure most similar
to that of ADH?
A) Oxytocin
B) ACTH
C) TSH
D) FSH
E) Prolactin
143. Which option would not be efficacious in the treatment of
patients with type 2 diabetes?
A) Glucocorticoids
B) Insulin injections
C) Thiazolidinediones
D) Sulfonylureas
E) Weight loss
144. Which of the following is most likely to occur in the early stages
of type 2 diabetes?
A) Increased insulin sensitivity
B) Decreased hepatic glucose output
C) Increased plasma levels of C-peptide
D) Increased plasma [β-hydroxybutyric acid]
E) Hypovolemia
145. What is the most common cause of respiratory distress syndrome
in neonates born at 7 months’ gestation?
A) Pulmonary edema due to pulmonary arterial hypertension
B) Formation of a hyaline membrane over the alveolar surface
C) Failure of the alveolar lining to form adequate amounts of
surfactant
D) Excessive permeability of the alveolar membrane to water
146. Which of the following is an expected circulatory change that
occurs after birth?
A) Opening of the ductus venosus
B) Opening of the foramen ovale
C) Opening of the ductus arteriosus
D) Closing of the ductus arteriosus
E) Closing of the inferior vena cava
147. A 45-year-old woman has a mass in the sella turcica that
compresses the portal vessels, disrupting pituitary access to
 p p p gp y
hypothalamic secretions. The secretion rate of which hormone
would most likely increase in this patient?
A) ACTH
B) GH
C) Prolactin
D) LH
E) TSH
148. Which of the following is not produced by osteoblasts?
A) Alkaline phosphatase
B) RANK ligand
C) Collagen
D) Pyrophosphate
E) Osteoprotegerin
149. Which set of findings would be expected in a patient with
primary hyperparathyroidism?

Plasma [1,25-(OH)2D3] Plasma [Phosphate] Urinary Ca2+ Excretion

A) ↑ ↑ ↑

B) ↑ ↓ ↑

C) ↑ ↓ ↓

D) ↓ ↓ ↑

E) ↓ ↑ ↓

F) ↓ ↑ ↑

150. A man who has been exposed to high levels of gamma radiation
is sterile due to destruction of the germinal epithelium of the
seminiferous tubules, although he has normal levels of
testosterone. Which of the following would be found in this
patient?
A) A normal secretory pa ern of GnRH
B) Normal levels of inhibin
C) Suppressed levels of FSH
D) Absence of Leydig cells

Questions 151 and 152

An experiment was conducted in which rats were injected with one of
two hormones or saline solution (control) for 2 weeks. Autopsies were then
performed, and organ weights were measured (in milligrams). Use this
information to answer Questions 151 and 152.

Control Hormone 1 Hormone 2

Pituitary 12.9 8.0 14.5

Thyroid 250 500 245

Adrenal glands 40 37 85

Body weight 300 152 175

151. What is hormone 1?

A) TRH
B) TSH
C) T4
D) ACTH
E) Cortisol
152. What is hormone 2?
A) TSH
B) T4
C) CRH
D) ACTH
E) Cortisol
153. An infant is born with yellow pigmentation in the skin and eyes.
What is the most likely cause of this?
A) Elevated circulating ACTH
B) Poor renal clearance of bilirubin
C) The lack of a fully functional liver at birth
D) Failure of the foramen ovale to close
E) Delayed onset of breathing

Answers
1. A) The freely circulating (unbound) hormone is the biologically active
hormone. Cholecalciferol is a prohormone and thus is not the
biologically active vitamin D hormone. In this question, cortisol, T4, and
aldosterone are all bound to carrier proteins.
TMP14 p. 929
2. D) Parasympathetic postganglionic fibers release acetylcholine that
activates muscarinic receptors on endothelium to produce NO and
increases cyclic guanosine monophosphate, which activates protein
kinase G, causing a reduction in intracellular calcium (also increasing
NO by positive feedback) and causing vasodilation.
TMP14 p. 1027
3. A) Estrogen compounds are believed to have an osteoblast-stimulating
effect. When the amount of estrogen in the blood falls to very low levels
after menopause, the balance between the bone-building activity of the
osteoblasts and the bone-degrading activity of the osteoclasts is tipped
toward bone degradation. When estrogen compounds are added as part
of hormone replacement therapy, the bone-building activity of the
osteoblasts is increased to balance the osteoclastic activity.
TMP14 pp. 949, 1045
4. A) ADH is made in the supraoptic nuclei of the hypothalamus. It is
transported in nerve fibers along with neurophysin carrier proteins that
pass through the pituitary stalk and terminate in the posterior pituitary.
TMP14 pp. 948–949
5. C) GH promotes several metabolic changes. These include a net increase
in amino acid uptake in the muscle and liver, a decrease in glucose
utilization and storage, and an increase in lipolysis. The net effect of GH
is to decrease glucose and lipid storage in adipose cells.
TMP14 pp. 943–944
6. A) Norepinephrine is released from the nerve terminals, and endothelin
is released from endothelial cells in the vasculature, causing
vasoconstriction of the vasculature.
TMP14 p. 1027
7. C) Type 2 diabetes mellitus is characterized by diminished sensitivity of
target tissues to the metabolic effects of insulin—that is, there is insulin
resistance. As a result, hepatic uptake of glucose is impaired, and
glucose release is enhanced. In muscle, the uptake of glucose is
impaired.
TMP14 pp. 985–986, 995
8. C) In acromegaly, high plasma levels of GH cause insulin resistance.
Consequently, glucose production by the liver is increased, and glucose
uptake by peripheral tissues is impaired.
TMP14 pp. 943–944, 996–997
9. A) During exercise, glucose utilization by muscle is increased, which is
largely independent of insulin.
TMP14 p. 985
10. A) Thecal cells do not have the capacity to produce estradiol because
they lack aromatase.
TMP14 pp. 1040, 1043, 1044
11. B) A very high concentration of testosterone in a female embryo will
induce formation of male genitalia. An adrenal tumor in the mother that
synthesizes testosterone at a high, uncontrolled rate could produce the
masculinizing effect.
TMP14 pp. 1043, 1044
12. A) Osmoreceptors in, or near, the hypothalamus are important
regulators of ADH. Hyperosmotic extracellular fluid causes the cells of
the hypothalamus to shrink and stimulates the release of ADH, which
promotes renal H2O reabsorption to restore the extracellular fluid to
isosmotic.
TMP14 p. 949
13. E) An individual with panhypopituitarism has generalized dysfunction
of the pituitary gland. GHRH from the hypothalamus is increased in an
a empt to restore the pituitary function. For similar reasons,
somatostatin is decreased. Because pituitary function is impaired,
growth hormone production is reduced, and because growth hormone
stimulates the production of somatomedin, its production is also
reduced.
TMP14 pp. 946–947
14. C) Antagonism of progesterone’s effects, dilation of the cervix, and
oxytocin all increase uterine smooth muscle excitability and facilitate
contractions and the onset of labor. LH would have no effect.
 Prostaglandin E2 strongly stimulates uterine smooth muscle contraction
and is formed at an increasing rate by the placenta late in gestation.
TMP14 pp. 1064, 1066
15. B) AVPR2 function is impaired in patients with nephrogenic diabetes
insipidus, rendering ADH ineffective at increasing H2O reabsorption in
the distal nephron. This causes a compensatory increase in the release of
ADH from the supraoptic nuclei of the hypothalamus. Patients with
diabetes insipidus run the risk of developing hypernatremia, and they
produce a large volume of dilute urine.
TMP14 pp. 381, 439
16. E) Thyroxine (T4) is the major thyroid hormone, along with
triiodothyronine (T3). An increase in the thyroid hormones a enuates
the production of thyroid-stimulating hormone (TSH) through negative
feedback inhibition.
TMP14 pp. 958–959
17. C) Thyroid hormones cause a general increase in basal metabolic rate.
With an increased metabolic rate, there is an increased metabolic
demand of the tissues which is the primary determinant of cardiac
output.
TMP14 p. 957
18. A) In a radioimmunoassay, there is too li le antibody to completely
bind the radioactively tagged hormone and the hormone in the fluid
(plasma) to be assayed. Thus, there is competition between the labeled
and endogenous hormone for binding sites on the antibody.
Consequently, if the amount of radioactive hormone bound to antibody
is low, this finding would indicate that plasma levels of endogenous
hormone are high.
TMP14 p. 936
19. A) Cold exposure is an important physiological stimulus for the
production and release of the thyroid hormones. Cold causes the
hypothalamic production of thyrotropin-releasing hormone, which
stimulates thyrotropes of the anterior pituitary to release thyroid-
stimulating hormone (TSH). The increased TSH stimulates the
 production of the thyroid hormones, including thyroxine, which helps
to relieve the physiological stress caused by the cold.
TMP14 pp. 958–959
20. B) The Sertoli cells of the seminiferous tubules secrete inhibin at a rate
proportional to the rate of production of sperm cells. Inhibin has a direct
inhibitory effect on anterior pituitary secretion of FSH. FSH binds to
specific receptors on the Sertoli cells, causing the cells to grow and
secrete substances that stimulate sperm cell production. The secretion of
inhibin thereby provides the negative feedback control signal from the
seminiferous tubules to the pituitary gland.
TMP14 p. 1033
21. B) A thyroid hormone–producing adenoma causes an increase in
thyroid hormones. Thus, one would expect an increase in both
circulating T4 and T3 caused by the adenoma. The increased T4 and T3
feeds back to inhibit the production and release of TRH from the
hypothalamus and TSH from the anterior pituitary to halt further
production of the thyroid hormones. However, the adenoma does not
respond to normal feedback regulation, and thus T3 and T4 remain
high.
TMP14 pp. 958–961
22. A) The corpus luteum is the only source of progesterone production,
except for minute quantities secreted from the follicle before ovulation.
The corpus luteum is functional between ovulation and the beginning of
menstruation, during which time the concentration of LH is suppressed
below the level achieved during the preovulatory LH surge.
TMP14 pp. 1046–1047
23. C) The high levels of TSH (outside the normal range) are indicative of
hypofunction of the thyroid, and this is further observed with the low
total T4. Thyroxine-binding globulin remains in the normal range,
making the best answer Hashimoto’s disease, which is the most
common form of hypothyroidism. Secondary hypothyroidism occurs in
response to failure of the pituitary gland to stimulate the thyroid.
Therefore, the high TSH rules out this possibility.
TMP14 pp. 961–962
24. E) Cholesterol desmolase is the key enzyme responsible for the
conversion of cholesterol to pregnenolone for the process of steroid
synthesis.
TMP14 p. 966
25. A) Aldosterone increases the Na+K+ ATPase in the basolateral
membrane of the principal cells and increases ENaC channels in the
luminal side. This creates a driving force for Na+ reabsorption and K+
excretion leading to hypokalemia. When aldosterone is low, K+
excretion is a enuated, leading to hyperkalemia.
TMP14 pp. 969–970
26. E) Anabolic steroids bind to testosterone receptors in the
hypothalamus, providing feedback inhibition of normal ovarian cycling
and preventing menstrual cycling as well as stimulation of osteoblastic
activity in the bones.
TMP14 pp. 1028, 1031
27. D) Chronically elevated aldosterone increases sodium and water
retention leading to an expansion of extracellular fluid volume.
Increased extracellular fluid leads to increased blood pressure, which
promotes pressure natriuresis, causing urinary sodium excretion to
come into balance. Thus, during a chronic infusion urinary sodium
excretion is not changed.
TMP14 p. 970
28. B) Right atrial pressure falls dramatically after the onset of breathing
because of a reduction in pulmonary vascular resistance, pulmonary
arterial pressure, and right ventricular pressure.
TMP14 pp. 1073–1075
29. B) Physiological stimuli for glucocorticoids, such as stress, cause the
hypothalamic production of corticotropin-releasing hormone (CRH).
CRH stimulates corticotropes from the anterior pituitary to release
corticotropin (or ACTH). Corticotropin promotes the production of
cortisol from the adrenal cortex to help alleviate the physiological
stressor.
TMP14 pp. 974–977
30. E) The metabolic actions of cortisol increase the availability of
circulating fuel sources in response to physiological stressors. Cortisol
impairs skeletal muscle glucose and amino acid uptake (although it
promotes hepatic amino acid uptake) and promotes lipolysis from
adipocytes. This has the net effect to increase plasma glucose, free fa y
acids, and amino acids.
TMP14 pp. 972–973
31. D) Glucose is normally filtered in the glomerulus and reabsorbed in the
proximal tubule. However, during untreated type I diabetes, the amount
of filtered glucose exceeds (180 mg/dl) the reabsorptive capacity of the
proximal tubule, increasing urinary osmolarity. This causes an increase
in water filtration, leading to frequent urination (polyuria).
TMP14 pp. 995
32. C) Aromatase causes conversion of testosterone to estradiol.
TMP14 p. 1043
33. D) Because of the loss of blood flow through the placenta, systemic
vascular resistance doubles at birth, which increases the aortic pressure
as well as the pressure in the left ventricle and left atrium.
TMP14 pp. 1073, 1074
34. C) Consuming a meal consisting of carbohydrate, protein, and fat will
stimulate the production and release of insulin, which promotes energy
storage. Insulin increases cell permeability to glucose to promote its
storage in the form of glycogen (liver) and fat through fa y acid
synthesis and storage in the adipose. Hormone-sensitive lipase
promotes the breakdown of fat to free fa y acids and is decreased in
response to insulin.
TMP14 pp. 985–989
35. B) Type I diabetes is associated with low insulin and thus an impaired
ability to store energy. Thus, in the absence of insulin, plasma free fa y
acids are increased to be made available for energy, liver glycogen is
depleted in an a empt to maintain plasma glucose, and skeletal muscle
mass decreases as protein is metabolized to make amino acids available
for energy.
TMP14 pp. 994–995
36. C) The postabsorptive state begins approximately 2 hours after a meal
when plasma glucose has typically returned to normal. During the
postabsorptive state, counter regulatory mechanisms are activated
which help to maintain constant plasma glucose concentration. Thus,
insulin is reduced to decrease the cellular uptake of glucose and
glucagon is increased to promote hepatic production and release of
glucose. After several hours, both growth hormone and cortisol are also
increased to reduce skeletal muscle and adipose uptake of glucose. The
net effect of these mechanisms is to prevent hypoglycemia.
TMP14 pp. 986, 991–992, 994
37. B) hCG also binds to LH receptors on the interstitial cells of the testes
of the male fetus, resulting in the production of testosterone in male
fetuses up to the time of birth. This small secretion of testosterone is
what causes the fetus to develop male sex organs instead of female sex
organs.
TMP14 pp. 1033, 1060–1061
38. D) Insulin is a peptide hormone that is derived from proinsulin. It
binds to an enzyme linked receptor composed of 2 alpha and 2 beta
subunits, leading to an increase in tyrosine kinase activity.
TMP14 pp. 984–985
39. E) The exchange of calcium between the bone fluid compartment and
the ECF serves as a rapid and fast-acting mechanism to buffer changes
in extracellular fluid calcium concentration.
TMP14 p. 1005
40. B) In nonpregnant woman, the only significant source of estrogen is
ovarian follicles or corpus luteae. Menstruation begins when the corpus
luteum degenerates. Menstruation ends when developing follicles
secrete estrogen sufficiently to raise circulating concentration to a level
that stimulates regrowth of the endometrium.
TMP14 pp. 1039, 1042, 1046–1047
41. B) As a result of negative feedback, plasma levels of TSH are a sensitive
index of circulating levels of unbound (free) thyroid hormones. High
plasma levels of TSH indicate inappropriately low levels of free thyroid
hormones in the circulation, such as are present with autoimmune
 destruction of the thyroid gland in persons with Hashimoto’s disease.
However, because elevated plasma levels of estrogen in pregnancy
increase hepatic production of TBG, the total amount (bound + free) of
thyroid hormones in the circulation is elevated. Plasma levels of thyroid
hormones are elevated in persons with Graves’ disease and in patients
with a pituitary TSH-secreting tumor, as well in patients given thyroid
extract for therapy.
TMP14 pp. 954, 958–962
42. F) The kidneys are essential for the conversion of inactive vitamin D
prohormones to the biologically active vitamin D hormone (1,25-
dihydroxycholecalciferol). This conversion is mediated by parathyroid
hormone acting in the proximal tubule epithelial cells. Therefore, with
impaired renal function, one would expect a decrease in plasma [1,25-
(OH)2D], along with a compensatory increase in PTH. The increased
plasma PTH causes bone resorption of calcium.
TMP14 p. 1015
43. D) The cells of the anterior pituitary that secrete LH and FSH, along
with the cells of the hypothalamus that secrete GnRH, are inhibited by
both estrogen and testosterone. The steroids taken by the woman caused
sufficient inhibition to result in cessation of the monthly menstrual
cycle.
TMP14 pp. 1033, 1047–1048
44. D) Patients with central diabetes insipidus have an inappropriately low
secretion rate of ADH in response to changes in plasma osmolality, but
their renal response to ADH is not impaired. Because plasma levels of
ADH are depressed, the ability to concentrate urine is impaired, and a
large volume of dilute urine is excreted. Loss of water tends to increase
plasma osmolality, which stimulates the thirst center and leads to a very
high rate of water turnover.
TMP14 p. 949
45. B) NO is the vasodilator that is normally released, causing vasodilation
in these arteries.
TMP14 pp. 1027, 1034
46. B) Hydroxyapatite is the major salt found in calcified bone, and the
osteon is composed of concentric layers of calcified bone. However, an
osteocyte is a quiescent cell that resides in lacunae (spaces). Osteoblasts
are the cells that actively form new bone.
TMP14 pp. 1003, 1005–1006
47. B) One of the major physiological roles for PTH is to promote the
conversion of 25-hydroxycholecalciferol, to the active 1,25-
dihydroxycholecalciferol in the proximal tubular epithelium. The other
choices represent normal physiological actions of PTH.
TMP14 pp. 1009–1012
48. D) Lethargy and myxedema are signs of hypothyroidism. Low plasma
levels of TSH indicate that the abnormality is in either the hypothalamus
or the pituitary gland. The responsiveness of the pituitary to the
administration of TRH suggests that pituitary function is normal and
that the hypothalamus is producing insufficient amounts of TRH.
TMP14 pp. 958–962
49. D) Inhibin prevents FSH release from the anterior pituitary,
preventing Sertoli cells from causing aromatization to produce estradiol.
TMP14 p. 1032
50. A) After menopause, the absence of feedback inhibition by estrogen
and progesterone results in extremely high rates of FSH secretion.
Women taking estrogen as part of hormone replacement therapy for
symptoms associated with postmenopausal conditions have suppressed
levels of FSH as a result of the inhibitory effect of estrogen.
TMP14 pp. 1050, 1051
51. D) Phosphodiesterase-5 receptors prevent hydrolysis of cyclic
guanosine monophosphate, thus keeping the levels high and
maintaining vasodilation.
TMP14 p. 1034
52. B) Glucagon stimulates glycogenolysis in the liver, but it has no
physiological effects in muscle. Both glucagon and cortisol increase
gluconeogenesis, and cortisol impairs glucose uptake by muscle.
TMP14 pp. 972–973, 992
53. C) Injection of insulin leads to a decrease in blood glucose
concentration. Hypoglycemia stimulates the secretion of GH, glucagon,
and epinephrine, all of which have counter regulatory effects to increase
glucose levels in the blood.
TMP14 pp. 945, 993–994
54. A) Prolonged fetal hypoxia during delivery can cause serious
depression of the respiratory center. Hypoxia may occur during delivery
because of compression of the umbilical cord, premature separation of
the placenta, excessive contraction of the uterus, or excessive anesthesia
of the mother.
TMP14 p. 1073
55. C) In general, peptide hormones are water soluble and are not highly
bound by plasma proteins. ADH, a neurohypophysial peptide hormone,
is virtually unbound by plasma proteins. In contrast, steroid and thyroid
hormones are highly bound to plasma proteins.
TMP14 pp. 929–930
56. C) The rise in intracellular calcium in the oocyte triggers the cortical
reaction in which granules that previously lay at the base of the plasma
membrane undergo exocytosis. This process leads to the release of
enzymes that “harden” the zona pellucida and prevent other sperm
from penetrating.
TMP14 p. 1025
57. B) Although estrogen and progesterone are essential for the physical
development of the breast during pregnancy, a specific effect of both
these hormones is to inhibit the actual secretion of milk. Even though
prolactin levels are increased 10- to 20-fold at the end of pregnancy, the
suppressive effects of estrogen and progesterone prevent milk
production until after the baby is born. Immediately after birth, the
sudden loss of both estrogen and progesterone secretion from the
placenta allows the lactogenic effect of prolactin to promote milk
production.
TMP14 pp. 1066–1067
58. C) The concentration of PTH strongly regulates the absorption of
calcium ion from the renal tubular fluid. A reduction in hormone
 concentration reduces calcium reabsorption and increases the rate of
calcium excretion in the urine. The other choices either have li le effect
on or decrease calcium excretion.
TMP14 pp. 1011–1012
59. B) A pituitary tumor secreting increased amounts of TSH would be
expected to stimulate the thyroid gland to secrete increased amounts of
thyroid hormones. TSH stimulates several steps in the synthesis of
thyroid hormones, including the synthesis of thyroglobulin. Increased
heart rate is among the many physiological responses to high plasma
levels of thyroid hormones. However, high plasma levels of thyroid
hormones do not cause exophthalmos. Immunoglobulins cause
exophthalmos in Graves’ disease, the most common form of
hyperthyroidism.
TMP14 pp. 952, 957, 961
60. A) Hemorrhage decreases the activation of stretch receptors in the atria
and arterial baroreceptors. Decreased activation of these receptors
increases ADH secretion.
TMP14 p. 949
61. E) Choices A to D are true: LH secretion will be suppressed (B) by the
negative feedback effect of the estrogen from the tumor; consequently,
she will not have menstrual cycles (C), and because she will not have
normal cycles, no corpus luteae will develop, so no progesterone will be
formed (A). The high levels of estrogen produced by the tumor will
provide stimulation of osteoblastic activity to maintain normal bone
activity (D).
TMP14 pp. 1044, 1045
62. D) After eating a meal, insulin secretion is increased. As a result, there
is an increased rate of glucose uptake by both the liver and muscle.
Insulin also inhibits hormone-sensitive lipase, which decreases
hydrolysis of triglycerides in fat cells.
TMP14 pp. 985–987, 992
63. B) The primary function of testosterone in the embryonic development
of males is to stimulate formation of the male sex organs.
TMP14 pp. 219–220, 364, 383, 405, 949–950
64. B) FSH stimulates the production of estrogens from Sertolis cells in the
testis. The Sertoli cells receive testosterone from Leydig cells (stimulated
by LH) and use the testosterone to make estrogen.
TMP14 p. 1023
65. C) The reduction in hydrogen ion indicated by the elevation in pH
increases the concentration of negatively charged phosphate ion species
available for ionic combination with calcium ions. Consequently, the
free calcium ion concentration is reduced.
TMP14 pp. 1011–1012
66. A) Prostate fluid contains calcium, citrate, phosphate and fibrinolysin.
The function of prostate fluid is to help neutralize the acidic
environment associated with other seminal fluids and thus improve
sperm motility.
TMP14 p. 1024
67. C) During suckling, stimulation of receptors on the nipples increases
neural input to both the supraoptic and paraventricular nuclei.
Activation of these nuclei leads to the release of oxytocin and
neurophysin from secretion granules in the posterior pituitary gland.
Suckling does not stimulate the secretion of appreciable amounts of
ADH.
TMP14 pp. 1066, 1067
68. C) In Conn’s syndrome, large amounts of aldosterone are secreted.
Because aldosterone causes sodium retention, hypertension is a
common finding in patients with this condition. However, the degree of
sodium retention is modest, as is the resultant increase in extracellular
fluid volume. This occurs because the rise in arterial pressure offsets the
sodium-retaining effects of aldosterone, limiting sodium retention and
permi ing daily sodium balance to be achieved.
TMP14 pp. 970, 981
69. C) The activity of stored sperm is a enuated as a result of the acidic
environment. After ejaculation, uterine and fallopian fluids wash away
inhibitory factors, allowing for full activation of the spermatozoa.
TMP14 pp. 1024–1025
70. D) DHEA sulfate produced by the fetal adrenal gland diffuses to the
placenta and is converted to DHEA and then to estradiol and provides
estradiol to the mother.
TMP14 pp. 1060, 1061
71. D) Sporadic nursing of the mother results in a lack of prolactin surge
because mechanosensors in the nipple cause prolactin release. Without
prolactin release, there is a lack of milk production, and the mother
eventually will not be able to provide milk for the baby.
TMP14 pp. 1066, 1067
72. A) Persons with Addison’s disease have diminished secretion of both
glucocorticoids (cortisol) and mineralocorticoids (aldosterone). In
persons with Cushing’s disease or Cushing’s syndrome, cortisol
secretion is elevated, but aldosterone secretion is normal. A low-sodium
diet is associated with a high rate of aldosterone secretion but a
secretion rate of cortisol that is normal. By inhibiting the generation of
angiotensin II and thus the stimulatory effects of angiotensin II on the
zona glomerulosa, administration of a converting enzyme inhibitor
would decrease aldosterone secretion without altering the rate of
cortisol secretion.
TMP14 pp. 971–972, 979–980
73. E) Spermatogonia undergo two rounds of meiotic division, leading to
the production of four haploid spermatids. The spermatids ultimately
differentiate into mature sperm.
TMP14 pp. 1021–1022
74. B) Progesterone is required to maintain the decidual cells of the
endometrium. If progesterone levels fall, as they do during the last days
of a nonpregnant menstrual cycle, menstruation will follow within a few
days, with loss of pregnancy. Administration of a compound that blocks
the progesterone receptor during the first few days after conception will
terminate the pregnancy.
TMP14 pp. 1060–1061
75. D) An inappropriately high rate of ADH secretion from the lung
promotes excess water reabsorption, which tends to produce
concentrated urine and a decrease in plasma osmolality. Low plasma
 osmolality suppresses both thirst and ADH secretion from the pituitary
gland.
TMP14 pp. 404, 949
76. B) A very high plasma concentration of progesterone maintains the
uterine muscle in a quiescent state during pregnancy. In the final month
of gestation, the concentration of progesterone begins to decline,
increasing the excitability of the muscle.
TMP14 pp. 971–972, 1027
77. D) The corpus luteum is the only source of progesterone. If she is not
having menstrual cycles, no corpus luteum is present.
TMP14 p. 1048
78. C) FSH stimulates the granulosa cells of the follicle to secrete estrogen.
TMP14 pp. 1040, 1048
79. E) In response to increased blood levels of glucose, plasma insulin
concentration normally increases during the 60-minute period following
oral intake of glucose. In type 1 diabetes mellitus, insulin secretion is
depressed. In contrast, in type 2 diabetes mellitus, insulin resistance is a
common finding, and at least in the early stages of the disease, there is
an abnormally high rate of insulin secretion.
TMP14 pp. 995–998
80. D) In Cushing’s syndrome, high plasma levels of cortisol impair
glucose uptake in peripheral tissues, which tends to increase plasma
levels of glucose. As a result, the insulin response to oral intake of
glucose is enhanced.
TMP14 pp. 996–998
81. B) In general, protein hormones cause physiological effects by binding
to receptors on the cell membrane. However, of the four protein
hormones indicated, only insulin activates an enzyme-linked receptor.
Aldosterone is a steroid hormone and enters the cytoplasm of the cell
before binding to its receptor.
TMP14 p. 932
82. D) hCG is secreted from the trophoblast cells beginning shortly after
the blastocyst implants in the endometrium.
TMP14 pp. 1060–1061
83. B) Aortic pressure increases due to the increase in left ventricular
pressure. The increase in left atrial pressure causes the foramen ovale to
close. The ductus arteriosus also closes within a short time after birth.
TMP14 pp. 1073–1075
84. A) Somnolence is a common feature of hypothyroidism. Palpitations,
increased respiratory rate, increased cardiac output, and weight loss are
all associated with hyperthyroidism.
TMP14 pp. 957, 962–963
85. C) An infant born of a mother with untreated diabetes will have
considerable hypertrophy and hyperfunction of the islets of Langerhans
in the pancreas. As a consequence, the infant’s blood glucose
concentration may fall to lower than 20 mg/dl shortly after birth.
TMP14 pp. 1078–1079
86. B) If a successful fertilization event occurs, followed by implantation in
the uterine wall, trophoblasts produce and secrete human chorionic
gonadotropin, which maintains the corpus luteum and its production of
estrogen and progesterone. Eventually, hCG levels decline in association
with increased placental production of progesterone and estrogen.
TMP14 p. 1042
87. E) Choices A to D would not stimulate PTH secretion. An increase in
calcium concentration (A) suppresses PTH secretion; calcitonin has li le
to no effect on PTH secretion (B); acidosis would increase free calcium in
the extracellular fluid, thereby inhibiting PTH secretion (C); and PTH-
releasing hormone does not exist (D).
TMP14 pp. 1001, 1011
88. C) Potassium is a potent stimulus for aldosterone secretion, as is
angiotensin II. Therefore, a patient consuming a high-potassium diet
would exhibit high circulating levels of aldosterone.
TMP14 p. 971
89. B) The decidua and trophoblasts provide the nutrition needed to
provide nourishment of the blastocyst.
TMP14 pp. 1057, 1060–1062
90. C) Steroid hormones are not stored to any appreciable extent in their
endocrine-producing glands. This is true for aldosterone, which is
produced in the adrenal cortex. In contrast, there are appreciable stores
of thyroid hormones and peptide hormones in their endocrine-
producing glands.
TMP14 p. 928
91. C) 1,25-Dihydroxycholecalciferol is formed only in the renal cortex.
Extensive renal disease reduces the amount of cortical tissue,
eliminating the source of this active calcium regulating hormone.
TMP14 p. 1015
92. C) The placenta cannot produce androgens but can only produce
DHEA by removal of the sulfate from DHEAS produced in the fetal
adrenal glands.
TMP14 p. 1060
93. A) The secretory phase of the endometrial cycle aligns with the luteal
phase of the ovarian cycle. Progesterone levels peak during this phase
and promote the vascularization and thickening of the endometrial
lining. If a fertilization event and subsequent implantation does not
occur, the corpus luteum involutes causing progesterone levels to fall
and the endometrial lining to slough off during menstruation.
TMP14 pp. 1046–1047
94. D) Because iodine is needed to synthesize thyroid hormones, the
production of thyroid hormones is impaired if iodine is deficient. As a
result of feedback, plasma levels of TSH increase and stimulate the
follicular cells to increase the synthesis of thyroglobulin, which results
in a goiter. Increased metabolic rate, sweating, nervousness, and
tachycardia are all common features of hyperthyroidism, not
hypothyroidism, due to iodine deficiency.
TMP14 pp. 960–963
95. C) Because of the effects of thyroid hormones to increase metabolism in
tissues, tissues vasodilate, thus increasing blood flow and cardiac
output. All the other choices increase in response to high plasma levels
of thyroid hormones.
TMP14 pp. 956–957
96. B) Sperm cell motility decreases as pH is reduced below 6.8. At a pH of
4.5, sperm cell motility is significantly reduced. However, the buffering
effect of sodium bicarbonate in the prostatic fluid raises the pH
somewhat, allowing the sperm cells to regain some mobility.
TMP14 p. 1024
97. B) A protein meal stimulates all three hormones indicated.
TMP14 pp. 945, 991, 993
98. C) Testosterone secreted by the testes in response to LH inhibits
hypothalamic secretion of GnRH, thereby inhibiting anterior pituitary
secretion of LH and FSH. Taking large doses of testosterone-like steroids
also suppresses the secretion of GnRH and the pituitary gonadotropic
hormones, resulting in sterility.
TMP14 p. 1033
99. C) Steroids with potent glucocorticoid activity tend to increase plasma
glucose concentration. As a result, insulin secretion is stimulated.
Increased glucocorticoid activity also diminishes muscle protein.
Because of feedback, cortisone administration leads to a decrease in
adrenocorticotropic hormone secretion and therefore a decrease in
plasma cortisol concentration.
TMP14 pp. 972–973
100. C) Inhibin is the hormone that has a negative feedback on the anterior
pituitary to prevent FSH from being released. Inhibin is produced by the
granulosa cells in the ovary.
TMP14 pp. 1040–1041
101. A) An increase in the concentration of PTH results in the stimulation
of existing osteoclasts and, over longer periods, increases the number of
osteoclasts present in the bone.
TMP14 pp. 1010–1011
102. B) In general, peptide hormones produce biological effects by binding
to receptors on the cell membrane. Peptide hormones are stored in
secretion granules in their endocrine-producing cells and have relatively
short half-lives because they are not highly bound to plasma proteins.
Protein hormones often have a rapid onset of action because, unlike
 steroid and thyroid hormones, protein synthesis is usually not a
prerequisite to produce biological effects.
TMP14 pp. 926, 929–932
103. D) A pituitary tumor secreting GH is likely to present as an increase in
pituitary gland size. The anabolic effects of excess GH secretion lead to
enlargement of the internal organs, including the kidneys. Because
acromegaly is the state of excess GH secretion after epiphyseal closure,
increased femur length does not occur.
TMP14 p. 947
104. A) GH and cortisol have opposite effects on protein synthesis in
muscle. GH is anabolic and promotes protein synthesis in most cells of
the body, whereas cortisol decreases protein synthesis in extrahepatic
cells, including muscle. Both hormones impair glucose uptake in
peripheral tissues and therefore tend to increase plasma glucose
concentration. Both hormones also mobilize triglycerides from fat stores.
TMP14 pp. 943–944, 972–973
105. B) If the mother has had adequate amounts of iron in her diet, the
infant’s liver usually has enough stored iron to form blood cells for 4 to
6 months after birth. However, if the mother had insufficient iron levels,
severe anemia may develop in the infant after about 3 months of life.
TMP14 pp. 1072, 1077
106. A) High plasma levels of steroids with glucocorticoid activity
suppress CRH and, consequently, ACTH secretion. Therefore, the
adrenal glands would actually atrophy with chronic cortisone treatment.
Increased plasma levels of glucocorticoids tend to cause sodium
retention and increase blood pressure. They also tend to increase plasma
levels of glucose and, consequently, stimulate insulin secretion and C-
peptide, which is part of the insulin prohormone.
TMP14 pp. 972–973, 976–977, 979–980
107. B) During the postovulatory phase of the cycle, there is a negative
feedback relationship between progesterone and estrogen and the
hypothalamic pituitary axis. Therefore, progesterone suppresses GnRH
release.
TMP14 pp. 1040–1042
108. C) SRY is the region on the Y chromosome that encodes a
transcription factor that causes differentiation of Sertoli cells from
precursors in testis. If SRY is not present, granulosa cells in the ovary are
produced.
TMP14 p. 1029
109. D) Fertilization of the ovum normally takes place in the ampulla of
one of the fallopian tubes.
TMP14 p. 1055
110. D) Because insulin secretion is deficient in persons with type 1
diabetes mellitus, there is increased (not decreased) release of glucose
from the liver. Low plasma levels of insulin also lead to a high rate of
lipolysis; increased plasma osmolality, hypovolemia, and acidosis are all
symptoms of uncontrolled type 1 diabetes mellitus.
TMP14 pp. 995–996
111. E) Under acute conditions, an increase in blood glucose concentration
will decrease GH secretion. GH secretion is characteristically elevated in
the chronic pathophysiological states of acromegaly and gigantism.
Deep sleep and exercise are stimuli that increase GH secretion.
TMP14 pp. 945–946
112. D) All the steroids listed include pregnenolone early in their
biosynthetic pathway. 1,25(OH)2D is derived from vitamin D and does
not include pregnenolone in its biosynthetic pathway.
TMP14 pp. 965–967, 1007–1008
113. D) Estrogen and, to a lesser extent, progesterone secreted by the
corpus luteum during the luteal phase have strong feedback effects on
the anterior pituitary gland to maintain low secretory rates of both FSH
and LH. In addition, the corpus luteum secretes inhibin, which inhibits
the secretion of FSH.
TMP14 p. 1042
114. D) Under chronic conditions, the effects of high plasma levels of
aldosterone to promote sodium reabsorption in the collecting tubules
are sustained. However, persistent sodium retention does not occur
because of concomitant changes that promote sodium excretion. These
changes include increased arterial pressure, increased plasma levels of
 g p p
atrial natriuretic peptide, and decreased plasma angiotensin II
concentration.
TMP14 pp. 961, 981
115. B) For reasons that are not entirely clear, the negative feedback
regulation between estrogen and LH that occurs throughout the ovarian
cycle briefly changes to a positive feedback mechanism. This occurs late
in the follicular phase, just prior to ovulation, when LH promotes
estrogen production and estrogen feeds back to stimulate the further
release of LH. This underlies the surge in LH just before ovulation.
TMP14 pp. 1040–1042
116. B) Circulating levels of free T4 exert biological effects and are
regulated by feedback inhibition of TSH secretion from the anterior
pituitary gland. Protein-bound T4 is biologically inactive. Circulating T4
is highly bound to plasma proteins, especially to TBG, which increases
during pregnancy. An increase in TBG tends to decrease free T4, which
then leads to an increase in TSH secretion, causing the thyroid to
increase thyroid hormone secretion. Increased secretion of thyroid
hormones persists until free T4 returns to normal levels, at which time
there is no longer a stimulus for increased TSH secretion. Therefore, in a
chronic steady-state condition associated with elevated TBG, high
plasma total T4 (bound and free) and normal plasma TSH levels would
be expected. In this pregnant patient, the normal levels of total T4, along
with high plasma levels of TSH, would indicate an inappropriately low
plasma level of free T4. Deficient thyroid hormone secretion in this
patient would be consistent with Hashimoto’s disease, the most
common form of hypothyroidism.
TMP14 pp. 954, 958–962
117. D) The motor neurons of the spinal cord of the thoracic and lumbar
regions are the sources of innervation for the skeletal muscles of the
perineum involved in ejaculation.
TMP14 pp. 1026, 1027
118. A) Trophoblasts invade the endometrial lining of the uterus and
provide nutrients to the growing blastocyst until the placenta if formed.
TMP14 pp. 1056–1057
119. B) Bone is deposited in proportion to the compressional load that the
bone must carry. Continual mechanical stress stimulates osteoblastic
deposition and calcification of bone.
TMP14 pp. 1006–1007
120. D) Prolactin is produced in the anterior pituitary from lactotrope cells
and is responsible for promoting milk production and secretion.
TMP14 pp. 1067–1068
121. B) In the absence of 11-β-hydroxysteroid dehydrogenase, renal
epithelial cells cannot convert cortisol to cortisone; therefore, cortisol
will bind to the mineralocorticoid receptor and mimic the actions of
excess aldosterone. Consequently, this would result in hypertension
associated with suppression of the renin-angiotensin-aldosterone
system, along with hypokalemia.
TMP14 pp. 968–970, 980–981
122. D) In target tissues, nuclear receptors for thyroid hormones have a
greater affinity for T3 than for T4. The secretion rate, plasma
concentration, half-life, and onset of action are all greater for T4 than for
T3.
TMP14 pp. 953–955
123. C) Blocking the action of FSH on the Sertoli cells of the seminiferous
tubules interrupts the production of sperm. Choice C is the only option
that is certain to provide sterility.
TMP14 p. 1033
124. C) Oxytocin is secreted from the posterior pituitary gland and carried
in the blood to the breast, where it causes the cells that surround the
outer walls of the alveoli and ductile system to contract. Contraction of
these cells raises the hydrostatic pressure of the milk in the ducts to 10 to
20 mm Hg. Consequently, milk flows from the nipple into the baby’s
mouth.
TMP14 pp. 1068–1069
125. B) Resulting from the growing fetal-placental unit, there is a large
increase in metabolic demand during a normal pregnancy. Given that
metabolic demand is the major determinant for cardiac output, the
 increase in metabolic demand during pregnancy causes an increase in
cardiac output.
TMP14 p. 1062
126. F) Persons with Cushing’s disease have a high rate of cortisol
secretion, but aldosterone secretion is normal. High plasma levels of
cortisol tend to increase plasma glucose concentration by impairing
glucose uptake in peripheral tissues and by promoting gluconeogenesis.
However, at least in the early stages of Cushing’s disease, the tendency
for glucose concentration to increase appreciably is counteracted by
increased insulin secretion.
TMP14 pp. 972–973, 979–980
127. A) In healthy patients, the secretory rates of ACTH and cortisol are
low in the late evening but high in the early morning. In patients with
Cushing’s syndrome (adrenal adenoma) or in patients taking
dexamethasone, plasma levels of ACTH are very low and are certainly
not higher than normal early morning values. In patients with
Addison’s disease, plasma levels of ACTH are elevated as a result of
deficient adrenal secretion of cortisol. The secretion of ACTH and
cortisol would be expected to be normal in Conn’s syndrome.
TMP14 pp. 977–980
128. B) Exercise stimulates GH secretion. Hyperglycemia, somatomedin,
and the hypothalamic inhibitory hormone somatostatin all inhibit GH
secretion. GH secretion also decreases as persons age.
TMP14 p. 945
129. C) A low-sodium diet would stimulate aldosterone but not cortisol
secretion. Increased atrial stretch associated with volume expansion
would stimulate atrial natriuretic peptide secretion but would not be
expected during a low-sodium diet.
TMP14 pp. 364, 405, 971–972
130. A) Adrenal gland hypofunction with Addison’s disease is associated
with decreased secretion of both aldosterone and cortisol. In Cushing’s
disease and Cushing’s syndrome associated with an ectopic tumor, the
mineralocorticoid-hypertension induced by high plasma levels of
cortisol would suppress aldosterone secretion. Neither a high-sodium
 diet nor administration of a converting enzyme inhibitor would affect
cortisol secretion.
TMP14 pp. 971-972, 979–980
131. B) Blood returning from the placenta through the umbilical vein
passes through the ductus venosus. The blood coming from the placenta
has the highest concentration of oxygen found in the fetus.
TMP14 p. 1074
132. B) Osteoporosis, hypertension, hirsutism, and hyperpigmentation are
all symptoms of Cushing’s syndrome associated with high plasma levels
of ACTH. If the high plasma ACTH levels were the result of either a
pituitary adenoma or an abnormally high rate of corticotropin-releasing
hormone secretion from the hypothalamus, the patient would likely
have an enlarged pituitary gland. In contrast, the pituitary gland would
not be enlarged if an ectopic tumor were secreting high levels of ACTH.
TMP14 pp. 979–980
133. B) Prolactin secretion is inhibited, not stimulated, by the hypothalamic
release of dopamine into the median eminence. GH is inhibited by the
hypothalamic-inhibiting hormone somatostatin. The secretion of LH,
TSH, and ACTH are all under the control of the releasing hormones
indicated.
TMP14 p. 942
134. B) Increased heart rate, increased respiratory rate, and decreased
cholesterol concentration are all responses to excess thyroid hormone.
TMP14 pp. 956–958
135. C) hCG is produced by syncytial trophoblasts from the growing
blastocyst. hCG is responsible for maintaining the corpus luteum which
produces estrogens and progesterone up through approximately 12
weeks’ gestation. After that time, the placenta makes enough estrogen
and progesterone to sustain the pregnancy.
TMP14 pp. 1059–1060
136. D) By age 45 years, only a few primordial follicles remain in the
ovaries to be stimulated by gonadotropic hormones, and the production
of estrogen decreases as the number of follicles approaches zero. When
estrogen production falls below a critical value, it can no longer inhibit
 g p g
the production of gonadotropic hormones from the anterior pituitary.
FSH and LH are produced in large quantities, but as the remaining
follicles become atretic, production by the ovaries falls to zero.
TMP14 pp. 1050, 1051
137. D) The binding of insulin to its receptor activates tyrosine kinase,
resulting in metabolic events leading to increased synthesis of fats,
proteins, and glycogen. In contrast, gluconeogenesis is inhibited.
TMP14 pp. 984–989
138. C) The secretion of chemical messengers (neurohormones) from
neurons into the blood is referred to as neuroendocrine secretion. Thus,
in contrast to the local actions of neurotransmi ers at nerve endings,
neurohormones circulate in the blood before producing biological
effects at target tissues. Oxytocin is synthesized from magnocellular
neurons whose cell bodies are located in the paraventricular and
supraoptic nuclei and whose nerve terminals terminate in the posterior
pituitary gland. Target tissues for circulating oxytocin are the breast and
uterus, where the hormone plays a role in lactation and parturition,
respectively.
TMP14 pp. 925, 948–950
139. C) The placenta is hypoxic under normal physiological conditions.
The diffusion of oxygen from the maternal circulation to the fetal
circulation is enhanced by the fact that fetal hemoglobin carries a greater
quantity of oxygen at a given blood Po2 than maternal hemoglobin. In
addition, the hemoglobin concentration is greater in the fetal circulation
than in the maternal circulation.
TMP14 p. 1058
140. B) Inhibition of the iodide pump decreases the synthesis of thyroid
hormones but does not impair the production of thyroglobulin by
follicular cells. Decreased plasma levels of thyroid hormones result in a
low metabolic rate and lead to an increase in TSH secretion. Increased
plasma levels of TSH stimulate the follicular cells to synthesize more
thyroglobulin. Nervousness is a symptom of hyperthyroidism and is not
caused by thyroid hormone deficiency.
TMP14 pp. 951–952, 956–960
141. D) As the blastocyst implants, the trophoblast cells invade the
decidua, digesting and imbibing it. The stored nutrients in the decidual
cells are used by the embryo for growth and development. During the
first week after implantation, this is the only means by which the
embryo can obtain nutrients. The embryo continues to obtain at least
some of its nutrition in this way for up to 8 weeks, although the placenta
begins to provide nutrition after about the 16th day beyond fertilization
(a li le more than 1 week after implantation).
TMP14 p. 1056
142. A) Both ADH and oxytocin are peptides containing nine amino acids.
Their chemical structures differ in only two amino acids.
TMP14 p. 949
143. A) Because glucocorticoids decrease the sensitivity of tissues to the
metabolic effects insulin, they would exacerbate diabetes.
Thiazolidinediones and weight loss increase insulin sensitivity.
Sulfonylureas increase insulin secretion. If weight loss and the
aforementioned drugs are ineffective, exogenous insulin may be used to
regulate blood glucose concentration.
TMP14 pp. 991, 996–997
144. C) In the early stages of type 2 diabetes, the tissues have a decreased
sensitivity to insulin. As a result, there is a tendency for plasma glucose
to increase, in part because decreased hepatic insulin sensitivity leads to
increased hepatic glucose output. Because of the tendency for plasma
glucose to increase, there is a compensatory increase in insulin secretion,
including C-peptide, which is part of the insulin prohormone.
Hypovolemia and increased production of ketone bodies, although
commonly associated with uncontrolled type 1 diabetes, are not
typically present in the early stages of type 2 diabetes.
TMP14 pp. 984, 994–998
145. C) One of the most characteristic findings in respiratory distress
syndrome is failure of the respiratory epithelium to secrete adequate
quantities of surfactant into the alveoli. Surfactant decreases the surface
tension of the alveolar fluid, allowing the alveoli to open easily during
inspiration. Without sufficient surfactant, the alveoli tend to collapse,
and there is a tendency to develop pulmonary edema.
TMP14 p. 1074
146. D) Several circulatory changes occur in the fetal circulation after birth.
These include the closing of physiological shunts. The ductus arteriosus
is a shunt that carries blood from the fetal pulmonary artery into the
descending aorta, thus bypassing the pulmonary circulation. At birth,
this shunt closes as systemic resistance increases, causing blood to flow
back into the pulmonary circulation through the shunt. Within hours of
birth, the walls of the ductus arteriosus close, and eventually the closing
becomes fibrous for permanent closure.
TMP14 pp. 1074–1075
147. C) The primary controllers of ACTH, GH, LH, and TSH secretion from
the pituitary gland are hypothalamic-releasing hormones. They are
secreted into the median eminence and subsequently flow into the
hypothalamic-hypophysial portal vessels before bathing the cells of the
anterior pituitary gland. Conversely, prolactin secretion from the
pituitary gland is influenced primarily by the hypothalamic-inhibiting
hormone dopamine. Consequently, obstruction of blood flow through
the portal vessels would lead to reduced secretion of ACTH, GH, LH,
and TSH but increased secretion of prolactin.
TMP14 p. 942
148. D) Osteoblasts secrete all of these except pyrophosphate. Secretions
(alkaline phosphatase) from osteoblasts neutralize pyrophosphate, an
inhibitor of hydroxyapatite crystallization. Neutralization of
pyrophosphate permits the precipitation of calcium salts into collagen
fibers.
TMP14 pp. 1004–1006
149. B) In primary hyperparathyroidism, high plasma levels of PTH
increase the formation of 1,25-(OH)2D3, which increases intestinal
absorption of calcium. This action of PTH, along with its effects to
increase bone resorption and renal calcium reabsorption, leads to
hypercalcemia. However, because of the high filtered load of calcium,
calcium is excreted in the urine. High plasma levels of PTH also
decrease phosphate reabsorption and increase urinary excretion, leading
to a fall in plasma phosphate concentration.
TMP14 pp. 1009–1012, 1014–1015
150. A) Gamma radiation destroys the cells undergoing the most rapid
rates of mitosis and meiosis, the germinal epithelium of the testes. The
man described is said to have normal testosterone levels, suggesting that
the secretory pa erns of GnRH and LH are normal and that his
interstitial cells are functional. Because he is not producing sperm, the
levels of inhibin secreted by the Sertoli cells would be maximally
suppressed, and his levels of FSH would be strongly elevated.
TMP14 p. 1033
151. B) In this experiment, the size of the thyroid gland increased because
TSH causes hypertrophy and hyperplasia of its target gland and
increased secretion of thyroid hormones. Increased plasma levels of
thyroid hormones inhibit the secretion of TRH, which decreases
stimulation of the pituitary thyrotropes, resulting in a decrease in the
size of the pituitary gland. Higher plasma levels of thyroid hormones
also increase metabolic rate and decrease body weight.
TMP14 pp. 955–955, 960
152. C) In this experiment, the size of the pituitary and adrenal glands
increased because CRH stimulates the pituitary corticotropes to secrete
ACTH, which in turn stimulates the adrenals to secrete corticosterone
and cortisol. Higher plasma levels of cortisol increase protein
degradation and lipolysis and therefore decrease body weight.
TMP14 pp. 972–974, 976–977
153. C) At birth, the neonatal liver is not fully functional. Therefore, it does
not excrete bilirubin properly over the first several days of life. The
increased concentration of circulating bilirubin gives infants a yellow
pigmentation in the skin and eyes (jaundice).
TMP14 pp. 1076–1077