Question 1

Which of the following best describes the mechanism of action for hydrophobic steroid hormones?

Accepted Answer

They bind to receptors in the cytosol or nucleus and alter gene transcription.

Question 2

A patient presents with extreme thirst and signs of dehydration. Laboratory tests reveal abnormally low levels of antidiuretic hormone (ADH). Which of the following best explains these symptoms?

Accepted Answer

Low ADH causes decreased water reabsorption in the kidneys, resulting in excessive urination and dehydration.

Question 3

Which hormone is released from the anterior pituitary in response to thyrotropin-releasing hormone (TRH) from the hypothalamus?

Accepted Answer

Thyroid-stimulating hormone (TSH)

Question 4

During a negative feedback loop regulating hormone secretion, which step immediately follows the detection of a stimulus by a receptor?

Accepted Answer

The control center processes the information and initiates a response.

Question 5

Which of the following is a direct effect of parathyroid hormone (PTH) on calcium ion homeostasis?

Accepted Answer

PTH increases osteoclast activity, releasing calcium ions from bone into the bloodstream.

Question 6

A patient with hyperaldosteronism is likely to exhibit which of the following laboratory findings?

Accepted Answer

Hypokalemia and high blood sodium levels

Question 7

Which hormone is secreted by the pineal gland and is involved in regulating the sleep-wake cycle?

Accepted Answer

Melatonin

Question 8

Which of the following best describes the role of insulin in glucose homeostasis?

Accepted Answer

Insulin promotes uptake and storage of glucose, lowering blood glucose levels.

Question 9

A patient with Addison’s disease is at risk for adrenal crisis. Which of the following best explains the physiological consequences of adrenal crisis?

Accepted Answer

Deficiency of cortisol and aldosterone leads to disruptions in fluid, electrolyte, and acid-base homeostasis.

Question 10

Which hormone is released by the heart in response to increased blood volume and triggers vasodilation and enhanced sodium excretion?

Accepted Answer

Atrial natriuretic peptide (ANP)

Question 11

Which of the following hormones is produced by the hypothalamus and stored in the posterior pituitary, playing a key role in milk let-down during breastfeeding?

Accepted Answer

Oxytocin

Question 12

Which of the following best describes the effect of epinephrine released from the adrenal medulla during a stress response?

Accepted Answer

Epinephrine increases heart rate, dilates airways, and mobilizes energy stores.

Question 13

Which of the following is a correct sequence for the negative feedback loop regulating thyroid hormone production?

Accepted Answer

Hypothalamus releases TRH → Anterior pituitary releases TSH → Thyroid gland releases T3 and T4

Question 14

Which of the following equations correctly represents the calculation of hormone half-life?

Accepted Answer

$$ t_{1/2} = \frac{0.693}{k} $$

Question 15

A patient with Graves’ disease is likely to exhibit which of the following symptoms due to overproduction of thyroid hormone?

Accepted Answer

Weight loss, increased heart rate, and heat intolerance

Question 16

Which hormone is secreted by alpha cells of the pancreatic islets and promotes glycogenolysis and gluconeogenesis?

Accepted Answer

Glucagon

Question 17

Which of the following best describes the effect of leptin secreted by adipose tissue?

Accepted Answer

Leptin induces satiety and prevents overeating.

Question 18

Which hormone is secreted by the kidneys in response to decreased blood oxygen concentration and stimulates erythrocyte production?

Accepted Answer

Erythropoietin (EPO)

Question 19

Which of the following best describes the antagonistic relationship between calcitonin and parathyroid hormone (PTH)?

Accepted Answer

Calcitonin decreases blood calcium levels, while PTH increases blood calcium levels.

Question 20

Which of the following best describes the effect of growth hormone (GH) on target tissues?

Accepted Answer

GH regulates growth of bone, skeletal muscle, cartilage, adipose tissue, and liver, with both short and long-term effects.

The Endocrine System: Structure, Function, and Regulation

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