Endocrine System Physiology Set 1

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Physiology (Endocrine System Set 1)

MCQ

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1. Parathyroid hormone directly :

A) controls the rate of 25-hydroxycholicalciferol formation

B) controls the rate of calcium transport in the mucosa of the small intestine

C) controls the rate of formation of calcium binding protein

D) controls the rate of formation of 1, 25-dihydroxycholicalciferol

E) stimulates renal tubular phosphate reabsorption

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2. Which of the following is most likely to produce the greatest increase in insulin secretion?

A) Amino acids

B) Amino acids and glucose

C) Amino acids and somatostatin

D) Glucose and somatostatin

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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 secretion by the parathyroid gland

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4. Exposure to UV light directly facilitates which of the following?

A) Conversion of cholesterol to 25-hydroxycholicalciferol

B) Conversion of 25-hydroxycholicalciferol to 1,25-dihydroxycholicalciferol

C) Transport of calcium into the extracellular fluid

D) Formation of calcium binding protein

E) Storage of vitamin D3 in the liver

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5. A 30-year-old woman is breast-feeding her infant. During suckling, which of the following
hormonal responses is expected?

A) Increased secretion of antidiuretic hormone (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

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6. A 40-year-old woman comes to the emergency room with a fracture in the neck of the femur.
Radiographs reveal generalized demineralization of the bone in the area. Her plasma calcium ion
concentration is significantly greater than normal: 12.2 mg/dL. Which of the following conditions is
consistent with this presentation?

A) Osteoporosis

B) Rickets

C) Hyperparathyroidism

D) Renal failure

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7. A man eats a low carbohydrate meal rich in proteins containing the amino acids that stimulate
insulin secretion. Which of the following responses accounts for the absence of hypoglycemia?

A) Suppression of growth hormone

B) Suppression of somatomedin C secretion

C) Stimulation of cortisol secretion

D) Stimulation of glucagon secretion

E) Stimulation of epinephrine secretion

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8. A 46-year-old man has “puffy” skin and is lethargic. His plasma thyroid-stimulating hormone
concentration is low and increases markedly when he is given thyrotropin-releasing hormone. Which of
the following 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

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9. 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

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10. Which of the following pairs is an example of the paracrine secretion?

A) Somatostatin—growth hormone secretion

B) Somatostatin—insulin secretion

C) Dopamine—prolactin secretion

D) Norepinephrine—corticotropin-releasing hormone secretion

E) Corticotropin-releasing hormone—adrenocorticotropic hormone secretion

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11. 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

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12. Which of the following hormones activate enzyme-linked receptors?

A) ADH

B) Insulin

C) ACTH

D) PTH

E) Aldosterone

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13. Some cells secrete chemicals into the extracellular fluid that act on cells in the same tissue. Which
of the following refers to this type of regulation?

A) Neural

B) Endocrine

C) Neuroendocrine

D) Paracrine

E) Autocrine

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14. A 55-year-old man has developed the syndrome of inappropriate antidiuretic hormone secretion due
to carcinoma of the lung. Which of the following physiological responses would be expected?

A) Increased plasma osmolality

B) Inappropriately low urine osmolality (relative to plasma osmolality)

C) Increased thirst

D) Decreased secretion of antidiuretic hormone from the pituitary gland

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15. Which of the following hormones is both synthesized and stored in the pituitary gland?

A) Growth hormone (GH)

B) GH releasing hormone (GHRH)

C) ADH

D) Somatostatin

E) Somatomedin

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16. Which of the following anterior pituitary hormones plays a major role in the regulation of a
nonendocrine target gland?

A) Adrenocorticotropic hormone

B) Thyroid-stimulating hormone

C) Prolactin

D) Follicle-stimulating hormone

E) Luteinizing hormone

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17. A patient has an elevated plasma thyroxine (T4
) concentration, a low plasma thyroid-stimulating
hormone (TSH) concentration, and a thyroid gland that is smaller than normal. Which of the following is
the most likely explanation for these findings?

A) Patient has a lesion in the anterior pituitary that prevents TSH secretion

B) Patient is taking propylthiouracil

C) Patient is taking thyroid extract

D) Patient is consuming large amounts of iodine

E) Patient has Graves disease

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18. Which of the following hormones is largely unbound to plasma proteins?

A) Cortisol

B) Thyroxine (T4 )

C) Antidiuretic hormone

D) Estradiol

E) Progesterone

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19. Which of the following decreases the rate of urinary excretion of calcium ions by the kidney?

A) Increase in calcitonin concentration in the plasma

B) Decrease in phosphate ion concentration in the plasma

C) Increase in the plasma level of parathyroid hormone

D) Metabolic acidosis

E) Increase in calcium ion activity in the plasma

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20. Which of the following changes would be expected to occur with increased binding of a hormone to
plasma proteins?

A) Increase in plasma clearance of the hormone

B) Decrease in half-life of the hormone

C) Increase in hormone activity

D) Increase in degree of negative feedback exerted by the hormone

E) Increase in plasma reservoir for rapid replenishment of free hormone

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21. . A patient has a goiter associated with high plasma levels of both thyrotropin-releasing hormone
(TRH) and thyroid-stimulating hormone (TSH). Her heart rate is elevated. This patient most likely has
which of the following?

A) Endemic goiter

B) Hypothalamic tumor secreting large amounts of TRH

C) Pituitary tumor secreting large amounts of TSH

D) Graves’ disease

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22. Which of the following stimulates the secretion of parathyroid hormone (PTH)?

A) Increase in extracellular calcium ion activity above the normal value

B) Increase in calcitonin concentration

C) Respiratory acidosis

D) Increased secretion of PTH-releasing hormone from the hypothalamus

E) None of the above

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23. A 40-year-old woman is placed on a high-potassium diet for several weeks. Which of the following
hormonal changes is most likely to occur?

A) Increased secretion of dehydroepiandrosterone

B) Increased secretion of cortisol

C) Increased secretion of aldosterone

D) Increased secretion of adrenocorticotropic hormone

E) Decreased secretion of corticotropin-releasing hormone

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24. Which of the following statements about antidiuretic hormone is true?

A) It is synthesized in the posterior pituitary gland

B) It increases salt and water reabsorption in the collecting tubules and ducts

C) It stimulates thirst

D) It has opposite effects on urine and plasma osmolality

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25. Which of the following is inconsistent with the diagnosis of Graves’ disease?

A) Increased heart rate

B) Exophthalmos

C) Increased plasma levels of triiodothyronine (T3 )

D) Increased plasma levels of thyroxine (T4 )

E) Increased plasma levels of thyroid-stimulating hormone

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Endocrine System Physiology Set 1

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