Download Toxicology - Problem Drill 11: Endocrine Toxicology Question No. 1

Toxicology - Problem Drill 11: Endocrine Toxicology
Question No. 1 of 10
Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as
needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
1. Which if the following is not considered to be an endocrine gland?
Question
(A) Parathyroid
(B) Adrenal
(C) Pituitary
(D) Thyroid
(E) They are all endocrine glands.
A. Incorrect!
The parathyroid is a gland.
B. Incorrect!
The adrenal gland is a gland.
C. Incorrect!
The pituitary gland is a gland.
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D. Incorrect!
The thyroid is a gland.
E. Correct!
All four choices are glands.
The endocrine system is a network of glands that synthesize, store and release
specific secretions directly into the bloodstream. These glands include the thyroid,
parathyroid, adrenal gland and pituitary gland.
The correct answer is (E).
Solution
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Question No. 2 of 10
Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as
needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
2. The adenohypophysis of the pituitary gland secretes which of the following:
Question
(A) Mineralcorticoids
(B) Glucocorticoids
(C) Testosterone
(D) Growth hormone
(E) None of the above
A. Incorrect!
Mineralcorticoids are secreted by the adrenal gland.
B. Incorrect!
Glucocorticoids are secreted by the adrenal gland.
C. Incorrect!
Testosterone is secreted by the testis and in minute amounts by the adrenal gland.
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D. Correct!
The adenohypophysis of the pituitary gland secretes growth hormone.
E. Incorrect!
One of the answers is correct.
The adenohypophysis secretes a number of important hormones into the body’s
circulation, including prolactin, growth hormone, adrenocorticotrophic hormone (or
ACTH), and thyroid-stimulating hormone (or TSH).
The correct answer is (D).
Solution
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Question No. 3 of 10
Instructions: (1) Read the problem statement and answer choices carefully (2) Work the problems
on paper as needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
3. ________________________ are/is observed with high frequency in lab rats
during long-term toxicology studies.
Question
(A) Pituitary lesions
(B) Cortical lesions
(C) Immunosuppression
(D) Neurotoxicity
(E) None of the above
A. Correct!
Pituitary lesions are observed with high frequency in lab rats during long-term
toxicology studies.
B. Incorrect!
Thinks of another type of lesion.
C. Incorrect!
Think of damage directly to the endocrine system.
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D. Incorrect!
Think of damage directly to the endocrine system.
B. Incorrect!
One of the answers is correct.
Pituitary lesions are observed with high frequency in lab rats during long-term
toxicology studies. These lesions are the result of spontaneous pituitary adenomas,
which are tumors of the pituitary gland. Pituitary adenomas are benign, which
means they do not spread to other portions of the brain. The incidence of pituitary
adenomas is determined by many factors, including strain, age, sex, reproductive
status, and diet.
The correct answer is (A).
Solution
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Question No. 4 of 10
Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as
needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
4. ______________ damages endothelial cells of the adrenal cortex.
Question
(A) Acrylonitrile
(B) Aniline
(C) Benzene
(D) Ozone
(E) None of the above
A. Correct!
Acrylonitrile damages endothelial cells of the adrenal cortex.
B. Incorrect!
Aniline causes lipid aggregation, not endothelial cell damage, in the adrenal cortex.
C. Incorrect!
Think of damage to the adrenal cortex, not the bone marrow.
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D. Incorrect!
Think of damage to the adrenal cortex, not the parathyroid gland.
E. Incorrect!
One of the answers is correct.
Cortical lesions are often associated with direct damage from chemicals, such as
acrylonitrile.
The correct answer is (A).
Solution
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Question No. 5 of 10
Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as
needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
5. The _______________ has the highest incidence of chemically-induced lesions
in the endocrine system.
Question
(A) Adrenal cortex
(B) Adrenal medulla
(C) Thyroid
(D) Parathyroid
(E) Kidney
A. Correct!
The adrenal cortex has the highest incidence of chemically-induced lesions in the
endocrine system.
B. Incorrect!
Think of another portion of the adrenal gland.
C. Incorrect!
Think of a gland associated with the kidneys.
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D. Incorrect!
Think of a gland associated with the kidneys.
E. Incorrect!
Kidneys are not endocrine glands.
The adrenal cortex has the highest incidence of chemically-induced lesions of any
gland in the endocrine system. The adrenal cortex is predisposed to toxicity for two
reasons. The first is that adrenal cortical cells contain large stores of lipids used as
substrates for steroidogenesis. Many compounds that are toxic to adrenal cortical
cells are lipophilic and tend to accumulate in these lipid-rich cells. The second
reason is that adrenal cortical cells have enzymes capable of metabolizing
xenobiotics. Just as in the liver, metabolism of xenobiotics can create more
reactive intermediates that are more toxic than the original compound.
The correct answer is (A).
Solution
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Question No. 6 of 10
Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as
needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
6. _______________ produced by the parathyroid gland regulates the body’s
calcium levels.
Question
(A) Prolactin
(B) Growth hormone
(C) Thyroid-stimulating hormone (TSH)
(D) Parathyroid hormone (PTH)
(E) None of the above
A. Incorrect!
Prolactin is produced by the pituitary gland.
B. Incorrect!
Growth hormone is produced by the pituitary gland.
C. Incorrect!
Thyroid-stimulating hormone (TSH) is produced by the pituitary gland.
Feedback
D. Correct!
Parathyroid hormone (PTH) produced by the parathyroid gland regulates the body’s
calcium levels.
E. Incorrect!
One of the answers is correct.
The parathyroid glands are small endocrine glands in the neck located behind the
thyroid gland. Most people have 4 parathyroid hormones, although some have 6 or
even as many as 8. The only function of the parathyroid gland is to regulate the
body’s calcium levels in a tight range through production of parathyroid hormone,
abbreviated PTH. When blood calcium levels drop below a certain point, calciumsensing receptors in the parathyroid gland are triggered to synthesize and release
PTH into the blood, where it acts against the hormone calcitonin to increase
gastrointestinal calcium absorption, break down bones to release calcium, and
promote calcium uptake by the kidneys.
The correct answer is (D).
Solution
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Question No. 7 of 10
Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as
needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
7. Thyroid hormone release can be blocked by:
Question
(A) Ozone
(B) Thiocyanate
(C) Reserpine
(D) Excess iodine
(E) None of the above
A. Incorrect!
Ozone affects the parathyroid gland, not the thyroid.
B. Incorrect!
Thiocyanate blocks iodine uptake, not thyroid hormone release.
C. Incorrect!
Reserpine affects the adrenal medulla, not the thyroid.
Feedback
D. Correct!
Thyroid hormone release can be blocked by excess iodine.
E. Incorrect!
One of the answers is correct.
Relatively few chemicals selectively inhibit secretion of thyroid hormone from the
thyroid gland. However, blockage of thyroid hormone release takes place when
there is excess iodine or excess lithium.
The correct answer is (D).
Solution
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Question No. 8 of 10
Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as
needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
8. L-asparaginase selectively destroys _________________.
Question
(A) Chief cells
(B) Oxyphil cells
(C) The adenohypophysis
(D) Adrenal cortical cells
(E) None of the above
A. Correct!
L-asparaginase selectively destroys chief cells.
B. Incorrect!
Think of the other type of cell in the parathyroid.
C. Incorrect!
Think of the parathyroid, not the pituitary.
Feedback
D. Incorrect!
Think of the parathyroid, not the adrenal cortex.
E. Incorrect!
One of the answers is correct.
Few chemicals or experimental conditions increase the incidence of parathyroid
tumors. However, parathyroid lesions can be caused by L-asparaginase, a
parathyroid toxicant which selectively destroys chief cells through an unknown
mechanism.
The correct answer is (A).
Solution
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Question No. 9 of 10
Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as
needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
9. Parathyroid hormone acts to:
Question
(A) Increase GI calcium absorption.
(B) Break down bones to release calcium.
(C) Promote calcium uptake by kidneys.
(D) All of the above
(E) None of the above
A. Incorrect!
Parathyroid hormone acts to increase GI calcium absorption, but it has other
actions, too.
B. Incorrect!
Parathyroid hormone acts to break down bones to release calcium, but it has other
actions, too.
C. Incorrect!
Parathyroid hormone acts to promote calcium uptake by kidneys, but it has other
actions, too.
Feedback
D. Correct!
Parathyroid hormone acts to increase GI calcium absorption, break down bones to
release calcium, and promote calcium uptake by kidneys.
E. Incorrect!
One of the answers is correct.
When blood calcium levels drop below a certain point, calcium-sensing receptors in
the parathyroid gland are triggered to synthesize and release PTH into the blood,
where it acts against the hormone calcitonin to increase gastrointestinal calcium
absorption, break down bones to release calcium, and promote calcium uptake by
the kidneys.
The correct answer is (D).
Solution
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Question No. 10 of 10
Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as
needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
10. ______________ causes adrenal medullary lesions.
Question
(A) Acrylonitrile
(B) Atenolol
(C) Benzene
(D) Ozone
(E) None of the above
A. Incorrect!
Think about damage to the adrenal medulla, not the adrenal cortex.
B. Correct!
Atenolol causes adrenal medullary lesions.
C. Incorrect!
Benzene causes bone marrow toxicity, not adrenal medullary lesions.
Feedback
D. Incorrect!
Think about damage to the adrenal medulla, not the parathyroid.
E. Incorrect!
One of the answers is correct.
Various toxicants are known to cause proliferative lesions of the adrenal medulla,
including long-term administration of growth hormone, as well as the drugs
nicotine, reserpine and atenolol.
The correct answer is (B).
Solution
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