CHAPTER 42—THE ENDOCRINE SYSTEM
MULTIPLE CHOICE
1. In nature, most animals have young during seasons of abundant food. The timing of these events are
dictated by environmental cues and
a.
metabolism.
b.
endocrine activity.
c.
catabolism.
d.
ecological events.
e.
thermodynamics.
2. Neural activity involves transmission of information through electrical events, in contrast endocrine
activity involves
a.
transport of hormones in the circulation system to target tissues.
b.
transport of hormones in neurons to target tissues.
c.
release of hormones in body fluids for transport.
d.
changes in neural activity for transport of hormones to target tissues.
e.
transmission of information through chemical reactions.
3. An important functional role of the endocrine system is to
a.
provide mechanisms for rapid responses to changes in the body.
b.
allow for mechanisms to control gene action.
c.
inhibit nervous system action on muscles and glands.
d.
maintain a constant, yet dynamic internal fluid environment.
e.
fight infection.
4. When a cell releases chemicals that act as signals into the extracellular fluid to affect cells, this is an
example of
a.
autocrine regulation.
b.
endocrine regulation.
c.
paracrine regulation.
d.
systemic regulation.
e.
exocrine regulation.
5. If a cell or tissue has a receptor for a hormone, that cell or tissue is
a.
an endocrine gland.
b.
a paracrine tissue.
c.
a neuroendocrine tissue.
d.
a target tissue.
e.
a signaling tissue.
6. Target tissues for steroid hormones and thyroid hormones do not have membrane receptors for these
hormones because they
a.
stimulate the cell by changes in electrical activity.
b.
are water soluble.
c.
enter the cell by ion channels.
d.
are small enough to diffuse directly into the cell.
e.
are soluble in the lipid bilayer.
7. Prostaglandins are
a.
protein molecules that act either by paracrine or autocrine mechanisms.
b.
fatty acid derivatives that act either by paracrine or autocrine mechanisms.
c.
neurotransmitters that act by paracrine mechanisms.
d.
amine molecules that act by neuroendocrine mechanisms.
e.
steroid molecules that are lipid soluble.
8. If a hormone is hydrophobic, is derived from cholesterol, and binds to membrane receptors, the type of
molecule is most likely
a.
a fatty acid.
b.
a steroid.
c.
a protein.
d.
an amine.
e.
a carbohydrate.
9. Hormone levels and action are determined by
a.
other hormones or releasing agents.
b.
carbohydrate activity.
c.
positive feedback systems.
d.
prostaglandins.
e.
touch receptors.
10. Select the chemical group that is NOT associated with any type of hormone.
a.
peptide and proteins
b.
fatty acid derivatives
c.
steroids
d.
polysaccharides
e.
amino acid derivatives
11. Oxytocin is a hormone that is involved with increasing contractions during childbirth. The action is
binding to membrane receptors and the result is increasing sodium and calcium. Oxytocin is most
likely a
a.
peptide or protein.
b.
steroid.
c.
carbohydrate.
d.
prostaglandin.
e.
fatty acid derivative.
12. The products of endocrine glands
a.
only affect their own tissue.
b.
provide feedback by paracrine action.
c.
always stimulate the target tissue.
d.
reach their target tissues via the circulation system.
e.
are released into body fluids, then into the circulation system.
13. Which type of hormones enter cells and have the primary action to either increase or decrease mRNA
production?
a.
steroid and peptide hormones
b.
steroid and phospholipid hormones
c.
thyroid and peptide hormones
d.
peptide and phospholipid hormones
e.
steroid and thyroid hormones
14. Cyclic AMP is a common second messenger, often associated with ____ hormones.
a.
peptide
b.
steroid
c.
protein
d.
fatty acid
e.
polysaccharide
15. Hormone action is associated with small quantities of hormone resulting in profound responses in
target tissues. This type of response is
a.
amplification.
b.
a second messenger response.
c.
a gene activation response.
d.
a cyclic AMP response.
e.
a growth factor response.
16. Select the appropriate order of hormone action.
a.
transduction, reception, response
b.
reception, response, transduction
c.
transduction, response, reception
d.
reception, transduction, response
e.
reception, translation, response
17. Your job is to determine if a steroid hormone is having an effect on its target tissue. Which of the
following would be an indication of activation of the target tissue by the hormone in question?
a.
increased cyclic AMP levels
b.
activation of G-proteins
c.
increased levels of mRNA
d.
increased calcium level in the cytoplasm
e.
increased polysaccharide levels in the cytoplasm
18. Glucose metabolism is regulated by several hormones. The predominant second messenger in these
mechanisms is
a.
glucagon.
b.
insulin.
c.
adenylyl cyclase.
d.
cyclic AMP.
e.
mRNA.
19. Calcium ions can act as second messengers by binding to ____, which then regulates other proteins.
a.
cyclic AMP
b.
calmodulin
c.
protein kinase
d.
phosphodiesterase
e.
adenylyl cyclase
20. Which of the following is INCORRECTLY paired?
a.
pancreas − insulin
b.
thyroid gland − thyroxine
c.
hypothalamus − melatonin
d.
adrenal cortex − glucocorticoids
e.
posterior pituitary − oxytocin
21. Which of the following hormones is INCORRECTLY paired with its target tissue?
a.
prolactin − mammary glands
b.
growth hormone − bone
c.
calcitonin − bone
d.
aldosterone − uterus
e.
pancreas − liver
22. If adenylyl cyclase were inhibited in animal cells
a.
binding of epinephrine to beta receptors would have no affect on cyclic AMP levels.
b.
binding of epinephrine to beta receptors would increase cyclic AMP levels.
c.
an increase in mRNA for cyclic AMP would occur.
d.
an increase in mRNA for more beta receptors would occur.
e.
epinephrine would not be able to bind to beta receptors.
23. In an experiment examining adrenergic receptors, epinephrine alone was not able to trigger an increase
in cAMP, but when beta receptors were fused with animal cells, there were high levels of cAMP. What
was occurring?
a.
activation of epinephrine.
b.
protein kinase inhibition.
c.
activation of adenylyl cyclase.
d.
protein kinase amplification.
e.
both activation of adenylyl cyclase and protein kinase amplification.
24. The pituitary gland is regulated most directly by the
a.
pineal gland.
b.
hypothalamus.
c.
pancreas.
d.
adrenal gland.
e.
thyroid gland.
25. Which of the following glands has a neurosecretory component as well as a component that is not
under direct neural control?
a.
the hypothalamus
b.
the pineal gland
c.
the adrenal gland
d.
the pituitary gland
e.
the parathyroid gland
26. The posterior lobe of the pituitary gland secretes
a.
ADH.
b.
TSH.
c.
oxytocin.
d.
ADH and oxytocin.
e.
ADH, oxytocin and TSH.
27. One of the main functions of the hypothalamus is to produce ____ hormones, which affect the ____
pituitary.
a.
releasing; posterior
b.
releasing; anterior
c.
activating; posterior
d.
amplification; anterior
e.
suppressing; anterior
28. Which of the following hormones does NOT promote growth of cells or tissues?
a.
ADH
b.
growth hormone
c.
insulin-like growth factors
d.
thyroid hormones
e.
prolactin
29. Given the following, select the correct sequence of events involved in regulating fluid balance.
1.
adrenal cortex secretes more glucocorticoids
2.
anterior pituitary secretes more ACTH
3.
hypothalamus secretes ACTH
4.
plasma levels of glucocorticoids increase
5.
anterior pituitary secretes less ACTH
a.
1, 2, 4, 5
b.
2, 1, 4, 5
c.
3, 1, 4, 5
d.
3, 4, 1, 2
e.
2, 4, 5, 1
30. The anterior pituitary secretes more ACTH, leading to more glucocorticoids in plasma, which causes
the anterior pituitary to then secrete less ACTH. This is an example of what type of hormone control?
a.
amplification
b.
positive feedback
c.
negative feedback
d.
cascading feedback
e.
both amplification and positive feedback
31. If melanocyte-stimulating hormone were increased, you would expect
a.
changes in kidney function for retention of water.
b.
increase in reproductive or estrus cycles.
c.
increase in heat loss from the body surface.
d.
increase in pigmentation in the skin.
e.
decrease in milk production in females.
32. The regulation of milk release, water balance and uterine contractions during childbirth are mediated
by the ____ gland.
a.
parathyroid
b.
pineal
c.
anterior pituitary
d.
posterior thyroid
e.
posterior pituitary
33. Anterior pituitary hormones have effects in all of the following EXCEPT
a.
ovaries and testes.
b.
mammary glands.
c.
thyroid glands.
d.
bone and muscle.
e.
kidneys.
34. The anterior pituitary hormone which has a generalized effect, having receptors on almost every cell in
the body, is
a.
prolactin.
b.
growth hormone.
c.
gonadotropin.
d.
ADH.
e.
ACTH.
35. Antiestrogens can bind to estrogen receptor sites
a.
without activation.
b.
without inhibition.
c.
and amplify the response.
d.
and prevent reception of hormone action.
e.
and increase growth of tumors.
36. Tamoxifen blocks the activity of estrogen in ____, but increases the activity of estrogen in ____.
a.
breast tissue; ovarian tissue
b.
uterine tissue; ovarian tissue
c.
uterine, tissue; breast tissue
d.
breast tissue; uterine tissue
e.
brain tissue; breast tissue
37. Different responses of the same hormone, or antiestrogen agent, is due to
a.
differences in luciferase activity.
b.
receptor sites for estrogen.
c.
differences in gene amplification.
d.
cyclic AMP levels.
e.
receptors in the hypothalamus.
38. Which of the following does NOT affect blood glucose levels?
a.
glucagon
b.
insulin
c.
epinephrine
d.
parathyroid hormone
e.
glucocorticoids
39. The actions of insulin and glucagon are
a.
synergistic.
b.
permissive.
c.
cooperative.
d.
antagonistic.
e.
mutualistic.
40. You are studying the hormonal control of metamorphosis in amphibians. If the anterior pituitary were
prevented from releasing TSH, predict the effect on tadpoles.
a.
Conversion to frogs would be increased five-fold.
b.
Metamorphosis would be extremely slow.
c.
Calcium secretion in tadpoles would be inhibited.
d.
Metabolism in tadpoles would be greatly decreased.
e.
Metamorphosis would be extremely slow and metabolism in tadpoles would be greatly
decreased.
41. During stressful situations, epinephrine initiates all of the following actions EXCEPT
a.
constriction of blood vessels to the skin.
b.
constriction of blood vessels to the heart.
c.
dilation of blood vessels to the brain.
d.
an increase in metabolic rate.
e.
an increase in blood glucose levels.
42. Overproduction of the mineralocoticoid ______ causes excessive water retention.
a.
cortisol
b.
aldosterone
c.
epinephrine
d.
catecholamine
e.
ADH
43. ____ is produced by the ____, which influences biological rhythms and the onset of sleep.
a.
Cortisol; pineal gland
b.
Melatonin; pituitary gland
c.
Parathyroid hormone; parathyroid gland
d.
Melatonin; pineal gland
e.
Aldosterone; adrenal gland
44. An adult who is suffering from hyperthyroidism
a.
is always tired.
b.
shows lack of emotions.
c.
is often hungry.
d.
sleeps a significant amount of the time.
e.
is never hungry.
45. Calcium levels are primarily under the control of
a.
calcitonin and thyroxine.
b.
parathyroid hormone and calcitonin.
c.
prolactin and oxytocin.
d.
parathyroid hormone and thyroxine.
e.
progesterone and ADH.
46. Which of the following is NOT produced by either the ovaries or testes?
a.
testosterone
b.
estrogen
c.
progesterone
d.
follicle-stimulating hormone
e.
androgens
47. One of the actions of the birth control pill is to
a.
prevent FSH and LH from being released from the hypothalamus.
b.
prevent ovulation.
c.
stop development of the uterine lining.
d.
increase plasma testosterone levels.
e.
synchronize the body’s biological clock.
48. Which of the following correctly describes the main difference between type 1 and type 2 diabetes?
a.
One causes hyperglycemia, while the other causes hypoglycemia.
b.
One demonstrates protein breakdown, while the other demonstrates protein synthesis.
c.
One leads to blindness, while the other leads to kidney disorder.
d.
One has insulin hypersecretion, while the other has insulin hyposecretion.
e.
One has insulin deficiency, while the other has insulin resistance.
49. Anabolic-androgenic steroids
a.
are synthetic forms of testosterone.
b.
are synthetic forms of estrogens.
c.
are used for treating early puberty.
d.
are natural variants of testosterone.
e.
are natural variants of estrogen.
50. High doses of AAS have been found to
a.
increase TSH levels.
b.
decrease gonadotrophins from the hypothalamus.
c.
increase natural testosterone.
d.
decrease thyroxine levels.
e.
have no effect on TSH levels.
51. High levels of hormones as a result of exogenous treatment will
a.
often produce excess blood levels of the hormones, causing feedback system to cause
further increases.
b.
often cause negative feedback systems to stop functioning in a normal fashion.
c.
convert negative feedback systems to positive feedback systems.
d.
have no effect on normal feedback systems.
e.
cause positive feedback systems to be inhibited.
52. Which of the following statements about steroid hormones in insects and humans is most accurate?
a.
An insect hormone injected into a human would have no effect.
b.
A human hormone injected in an insect would have no effect.
c.
The reaction pathways stimulated by steroid hormones in insects and humans are similar.
d.
The reaction pathways stimulated by steroid hormones in insects and humans are different.
e.
Insects do not have steroid hormones.
53. Select the hormone that is NOT involved in crustacean molting.
a.
molt-inhibiting hormone
b.
juvenile hormone
c.
brain hormone
d.
ecdysone
e.
molt-stimulating hormone
54. When molt-inhibiting hormone is prevented from being secreted
a.
ecdysone levels increase.
b.
ecdysone levels decrease.
c.
molting is inhibited.
d.
growth is inhibited.
e.
growth is stimulated.
55. The only gene successfully targeted for breast cancer prevention is the
a.
estrogen promoter gene.
b.
estrogen receptor gene.
c.
uterine promoter gene.
d.
uterine receptor gene.
e.
breast promoter gene.
56. The reason some individual hormones have multiple effects on different target tissues is that
a.
gene transcription is altered.
b.
second messengers trigger cascade or amplification effects.
c.
many different cells in different tissues have specific receptors for the hormone.
d.
only a small amount of the hormone is required for its effect.
e.
hormones can conform to multiple receptors.
57. Target tissues often have receptors for multiple hormones. The response of the target tissue depends on
a.
blood levels of and interactions between the hormones that affect it.
b.
blood levels of the hormones that affect it.
c.
interactions between hormones.
d.
blood levels of and interactions between the hormones that affect it and the effects of other
signaling molecules, such as prostaglandins.
e.
growth hormones levels.
58. Stress can have a significant effect on the body. Chronic stress
a.
may lead to excessive stimulation of neurons.
b.
is associated with elevated levels of epinephrine from the adrenal cortex.
c.
is associated with elevated levels of cortisol from the adrenal cortex.
d.
may lead to increased blood flow to the brain, especially the hippocampus.
e.
may suppress stimulation of neurons.
59. Hormone A binds to intracellular receptors in its target tissue. As a result of Hormone A, the target
tissue is now sensitive or responsive to Hormone B. The action of Hormone A was to
a.
decrease mRNA for Hormone A receptors.
b.
increase receptor sites for Hormone B.
c.
increase receptor sits for Hormone A.
d.
increased cyclic AMP levels which activated receptors for hormone B.
e.
decrease receptor sites for Hormone B.
60. Negative feedback loops to the hypothalamus and the pituitary operate to regulate the levels of all of
the following hormones EXCEPT
a.
cortisol.
b.
thyroid hormones.
c.
insulin.
d.
testosterone.
e.
progesterone.
61. Select the endocrine gland whose secretory function is under direct control of the sympathetic pre–
ganglionic neuron.
a.
pancreas
b.
thyroid
c.
adrenal medulla
d.
adrenal cortex
e.
posterior pituitary
MATCHING
Match each of the following concepts with the most appropriate response.
a.
Contains four iodine atoms
b.
Second messenger
c.
Opposite effect of molt-inhibiting hormone
d.
Hormone produced by the adrenal cortex that regulates sodium and potassium levels
e.
Insulin deficiency
f.
Typically steroids and affect gene activation
g.
Hormones that either stimulate or inhibit another cell or tissue
h.
Pituitary dwarfism
i.
Small activation, cascading response
j.
Target tissue of melatonin
k.
Signal molecule released by a cell into the extracellular fluid having a localized response
l.
Paracrine or autocrine regulation
62. aldosterone
63. cyclic AMP
64. paracrine regulation
65. tropic hormones
66. thyroxine
67. ecdysone
68. hydrophobic hormone
69. amplification
70. type 1 diabetes
71. suprachiasmatic nucleus
72. hyposecretion of growth hormone
73. prostaglandins
849
Choice
Select from the figure the appropriate endocrine gland. (Answers may be used more than once.)
74. production and release of insulin
75. a portion is neuroendocrine and a portion is under hormonal control of the hypothalamus
76. production site of androgens
77. primary calcium regulation
78. ADH production
79. a portion of this gland is a postganglionic sympathetic neuron
80. controls biological rhythms
81. hormones from this gland play an important role in metamorphosis in amphibians
82. Hormones from these glands stimulate other glands to produce hormones (two answers)
83. production and release of calcitonin
84. gland that produces progesterone that is under the control of GnRH
85. the hormone produced by this gland works in a synergistic fashion with Vitamin D
86. production site of the hormone that promotes growth in bones and muscles
87. production site of hormone involved in milk production
88. production site of hormone involved in water balance by increasing nephron permeability to water
89. site of release of oxytocin
851
MODIFIED TRUE/FALSE
If the statement is true, answer “T“. If the statement is false, answer “F” and make it correct by
changing the underlined word(s) and writing the correct word(s) in the answer blank(s).
90. Hormones are cleared from the body by endocrine glands.
91. Insulin is produced and released from the exocrine pancreas.
92. Ecdysone inhibitors could be used as insecticides.
93. Prostaglandins are under endocrine regulation.
94. Oxytocin is secreted by the posterior pituitary only in females.
95. Increases in MSH could result in increased pigmentation.
96. Cyclic AMP activity is associated with hydrophobic hormones.
97. Fruit flies, mollusks, and humans have insulin-like hormones and receptors, even though molecular
studies suggest that their last common ancestor existed more than 800 million years ago.
98. Estrogens can both induce cancer cell proliferation and prevent breast cancer.
SHORT ANSWER
99. Describe amplification of hormone action.
100. Explain negative feedback control using thyroid hormones as an example.
101. Compare and contrast receptor recognition between a hydrophobic and hydrophilic hormone.
ESSAY
102. A patient is having blood glucose problems. Plasma glucose levels are very low, a condition called
hypoglycemia. The problem is not associated with insulin, but with the secretion of glucocorticoids.
How would you evaluate the patient to determine where in the feedback system the problem is
located?
103. If a hormone caused an increase in protein kinase activity, predict the type of hormone responsible and
the intracellular signaling mechanism of its action.