Question 1

Which of the following best describes the difference between endocrine and exocrine glands?

Accepted Answer

Endocrine glands release hormones into the bloodstream, while exocrine glands release substances onto epithelial surfaces via ducts.

Question 2

A patient presents with symptoms of high blood pressure, muscle weakness, and abnormal heart rhythms. Laboratory tests reveal excessive aldosterone secretion. Which of the following best explains the physiological mechanism behind these symptoms?

Accepted Answer

Aldosterone increases sodium reabsorption and potassium excretion, leading to hypertension and hypokalemia.

Question 3

Which of the following hormones is synthesized from cholesterol and acts on intracellular receptors to directly activate gene transcription?

Accepted Answer

Cortisol

Question 4

A patient with a pituitary tumor is found to have elevated levels of ACTH. Which of the following is a likely consequence?

Accepted Answer

Increased secretion of cortisol from the adrenal cortex

Question 5

Which of the following best describes the mechanism of action for water-soluble hormones?

Accepted Answer

They bind to plasma membrane receptors and activate second messenger systems such as cAMP.

Question 6

A patient is experiencing symptoms of myxedema, including low metabolic rate and lethargy. Laboratory tests reveal low levels of thyroid hormone. Which of the following is the most likely cause?

Accepted Answer

Hyposecretion of TSH or iodine deficiency

Question 7

Which of the following scenarios best illustrates the concept of 'permissiveness' in hormone interactions?

Accepted Answer

Thyroid hormone must be present for reproductive hormones to exert their full effects on development.

Question 8

Which of the following equations correctly represents the half-life ($$t_{1/2}) of a $$hormone, given its rate constant $$k$$?

Accepted Answer

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

Question 9

A patient with diabetes insipidus is likely to have a deficiency in which hormone, and what is a classic symptom?

Accepted Answer

Antidiuretic hormone (ADH); excessive urine output

Question 10

Which of the following best explains why removal of the thyroid gland does not significantly affect calcium homeostasis in adults?

Accepted Answer

Calcitonin, produced by the thyroid, has a minor role in calcium regulation compared to parathyroid hormone.

Question 11

Which hormone is primarily responsible for stimulating the production of red blood cells in response to hypoxia?

Accepted Answer

Erythropoietin (EPO)

Question 12

A patient with Graves’ disease is likely to exhibit which of the following symptoms, and what is the underlying mechanism?

Accepted Answer

High metabolic rate due to antibodies that mimic TSH and stimulate thyroid hormone release

Question 13

Which of the following best describes the effect of parathyroid hormone (PTH) on blood calcium levels?

Accepted Answer

PTH increases blood calcium by stimulating osteoclasts and enhancing calcium reabsorption in the kidneys.

Question 14

Which of the following is a direct effect of insulin on target cells?

Accepted Answer

Enhances membrane transport of glucose into muscle and fat cells

Question 15

A patient with Addison’s disease is likely to present with which of the following laboratory findings?

Accepted Answer

Low blood glucose and low sodium levels

Question 16

Which of the following best describes the role of the hypothalamic-pituitary-target endocrine organ feedback loop?

Accepted Answer

It allows hormones from target organs to inhibit the release of anterior pituitary hormones via negative feedback.

Question 17

Which hormone is released in response to neural stimuli from the sympathetic nervous system and is responsible for the 'fight or flight' response?

Accepted Answer

Epinephrine

Question 18

Which of the following best explains why a patient with chronic low blood calcium might develop tetany?

Accepted Answer

Low calcium decreases the threshold for action potentials, causing spontaneous muscle contractions.

Question 19

Which of the following best describes the effect of atrial natriuretic peptide (ANP) on blood pressure?

Accepted Answer

ANP decreases blood pressure by inhibiting renin and aldosterone secretion.

The Endocrine System: Structure, Function, and Regulation

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