Question 1

Estradiol is an example of

Accepted Answer

A)   an androgen.
B)   an estrogen.
C)   a progestin.
D)   a catecholamine.
E)   a glucocorticoid. B

Question 2

Shortly after ingesting a big plate of carbohydrate-rich pasta, you measure your blood's hormone levels. What results would you expect, compared to before the meal?

Accepted Answer

A)   high insulin, low glucagon
B)   low insulin, low glucagon
C)   high insulin, high glucagon
D)   low insulin, high glucagon
E)   low insulin, no change in glucagon A

Question 3

The increased contraction of the human uterus during labor and delivery is at least partially due to the actions of

Accepted Answer

A)   ecdysone.
B)   glucagon.
C)   thyroxine.
D)   oxytocin.
E)   growth hormone. D

Question 4

In a positive-feedback system where hormone A alters the amount of protein X

Accepted Answer

A)   an increase in A always produces an increase in X.
B)   an increase in X always produces a decrease in A.
C)   a decrease in A always produces an increase in X.
D)   a decrease in X always causes a decrease in A.
E)   it is impossible to predict how A and X affect each other.

Question 5

The hypothalamus modulates hormone secretion by the anterior pituitary by means of

Accepted Answer

A)   peptide hormones.
B)   steroid hormones.
C)   electrical synapses.
D)   neurotransmitters.
E)   paracrine signals.

Question 6

Which of the following is the most likely explanation for hypothyroidism in a patient whose iodine level is normal?

Accepted Answer

A)   greater production of T₃ than of T₄
B)   hyposecretion of TSH
C)   hypersecretion of TSH
D)   hypersecretion of MSH
E)   a decrease in the thyroid secretion of calcitonin

Question 7

Melatonin is secreted by

Accepted Answer

A)   the hypothalamus during the day.
B)   the pineal gland during the night.
C)   the autonomic nervous system during the winter.
D)   the posterior pituitary gland during the day.
E)   the thyroid gland during cold seasons.

Question 8

Winter hibernation and spring reproduction in bears are cued by seasonal changes in the secretion of

Accepted Answer

A)   melatonin from the pineal gland.
B)   melatonin from the hypothalamus.
C)   thyroxine from the anterior pituitary gland.
D)   acetylcholine from the pineal gland.
E)   thyroid-stimulating hormone from the posterior pituitary gland.

Question 9

During mammalian labor and delivery, the contraction of uterine muscles is enhanced by oxytocin. This is an example of

Accepted Answer

A)   a negative feedback system.
B)   a hormone that acts in an antagonistic way with another hormone.
C)   a hormone that is involved in a positive feedback loop.
D)   signal transduction immediately changing gene expression in its target cells.
E)   the key role of the anterior pituitary gland in regulating uterine contraction.

Question 10

The steroid hormone that coordinates molting in arthropods is

Accepted Answer

A)   ecdysone.
B)   glucagon.
C)   thyroxine.
D)   oxytocin.
E)   growth hormone.

Question 11

Epinephrine is an example of

Accepted Answer

A)   an androgen.
B)   an estrogen.
C)   a progestin.
D)   a catecholamine.
E)   a glucocorticoid.

Question 12

When the beta cells of the pancreas release insulin into the blood,

Accepted Answer

A)   the blood glucose levels rise to a set point and stimulate glucagon release.
B)   the skeletal muscles and the adipose cells take up glucose at a faster rate.
C)   the liver catabolizes glycogen.
D)   the alpha cells of the pancreas release glucose into the blood.
E)   the kidneys begin gluconeogenesis.

Question 13

Testosterone is an example of

Accepted Answer

A)   an androgen.
B)   an estrogen.
C)   a progestin.
D)   a catecholamine.
E)   an adrenal steroid.

Question 14

A chemical signal operating in a paracrine manner is one that

Accepted Answer

A)   is active at a neuronal synapse.
B)   affects only the cells that synthesize the paracrine signal.
C)   requires transport in the blood before it can act on its target cells.
D)   evokes responses from all parts of the vascular system.
E)   must move through the air before it reaches its target cells.

Question 15

Suppose that substance X is secreted by one cell, travels via interstitial fluid to a neighboring cell, and produces an effect on that cell. All of the following terms could describe this substance except

Accepted Answer

A)   paracrine signal.
B)   neurotransmitter.
C)   prostaglandin.
D)   pheromone.
E)   growth factor.

Question 16

A fantasy movie features a caterpillar that never matures into an adult, but simply gets larger and larger with each molt. It might be possible that the caterpillar did not mature into an adult because of

Accepted Answer

A)   a lack of ecdysone.
B)   a lack of juvenile hormone.
C)   a decreased level of ecdysone.
D)   an increased level of juvenile hormone.
E)   a lack of melatonin.

Question 17

During a stressful interval

Accepted Answer

A)   TSH stimulates the adrenal cortex and medulla to secrete acetylcholine.
B)   the alpha cells of islets secrete insulin and simultaneously the beta cells of the islets secrete glucagon.
C)   ACTH stimulates the adrenal cortex, and neurons of the sympathetic nervous system stimulate the adrenal medulla.
D)   the posterior pituitary gland secretes more growth hormones.
E)   the calcium levels in the blood are increased due to actions of two antagonistic hormones, epinephrine and norepinephrine.

Question 18

Portal blood vessels connect two capillary beds found in the

Accepted Answer

A)   hypothalamus and thalamus.
B)   anterior pituitary and posterior pituitary.
C)   hypothalamus and anterior pituitary.
D)   posterior pituitary and thyroid gland.
E)   anterior pituitary and adrenal gland.

Question 19

The reason that the steroid hormone aldosterone affects only a small number of cells in the body is that

Accepted Answer

A)   only its target cells get exposed to aldosterone.
B)   only its target cells contain aldosterone receptors.
C)   it is unable to enter nontarget cells.
D)   nontarget cells destroy aldosterone before it can produce any effect.
E)   nontarget cells convert aldosterone to a hormone to which they do respond.

Question 20

A paracrine signal that relaxes smooth muscle cells is

Accepted Answer

A)   nitric oxide.
B)   vitamin D.
C)   testosterone.
D)   cortisol.
E)   antidiuretic hormone.

Exam 45: Hormones and the Endocrine System