Question 1

Which of the following best describes the main difference in the mechanism of signal transmission between the nervous system and the endocrine system?

Accepted Answer

The nervous system uses action potentials and neurotransmitters for rapid, localized signaling, while the endocrine system uses hormones for slower, widespread signaling.

Question 2

A hormone binds to a receptor on the cell membrane and activates a G protein, which then activates adenylate cyclase. Adenylate cyclase converts ATP to cAMP, which then activates protein kinase A. What is the role of cAMP in this signaling pathway?

Accepted Answer

cAMP acts as a secondary messenger that amplifies the signal inside the cell.

Question 3

Which of the following hormones is most likely to require a transport protein in the blood and why?

Accepted Answer

Cortisol, because it is a steroid hormone and is not water-soluble.

Question 4

A patient has a tumor that is secreting excess parathyroid hormone (PTH). Which of the following physiological effects would you expect to observe?

Accepted Answer

Increased blood calcium levels due to increased bone resorption.

Question 5

Which of the following statements about steroid hormones is correct?

Accepted Answer

Steroid hormones are synthesized from cholesterol and can cross the cell membrane to bind intracellular receptors.

Question 6

Which hormone is released from the posterior pituitary and acts on the kidneys to promote water reabsorption?

Accepted Answer

Antidiuretic hormone (ADH)

Question 7

A researcher blocks the hypothalamic-hypophyseal portal system in an experimental animal. Which of the following effects would most likely be observed?

Accepted Answer

Decreased stimulation of the anterior pituitary by hypothalamic hormones.

Question 8

Which of the following best explains why second messenger systems can produce large cellular responses to small amounts of hormone?

Accepted Answer

Second messenger systems amplify the signal at multiple steps, so one hormone molecule can activate many intracellular molecules.

Question 9

Which hormone is derived from tryptophan and helps regulate circadian rhythms?

Accepted Answer

Melatonin

Question 10

Which of the following is NOT a function of hormones?

Accepted Answer

Initiating voluntary muscle contraction for movement

Question 11

Which hormone is NOT produced by the anterior pituitary gland?

Accepted Answer

Antidiuretic hormone (ADH)

Question 12

A signaling molecule is released from a cell and acts on neighboring cells in the same tissue. This type of signaling is best described as:

Accepted Answer

Paracrine

Question 13

Which of the following best describes the role of tropic hormones?

Accepted Answer

They stimulate the release of other hormones from endocrine glands.

Question 14

Which of the following is a correct pairing of hormone and its primary function?

Accepted Answer

Aldosterone – increases sodium reabsorption in the kidneys

Question 15

Which of the following statements about hormone receptors is correct?

Accepted Answer

Steroid hormones bind to intracellular receptors, while peptide hormones bind to membrane-bound receptors.

Question 16

Which of the following best explains why the effects of the endocrine system are generally longer-lasting than those of the nervous system?

Accepted Answer

Hormones remain in the bloodstream longer than neurotransmitters remain in the synaptic cleft.

Question 17

Which of the following is a correct sequence for the hypothalamic-pituitary-adrenal (HPA) axis in response to stress?

Accepted Answer

Hypothalamus releases CRH → Anterior pituitary releases ACTH → Adrenal cortex releases cortisol

Question 18

Which of the following best describes the amplification that occurs in a second messenger system?

Accepted Answer

One hormone molecule can activate many G proteins, each of which can activate many adenylate cyclase enzymes, leading to the production of many cAMP molecules.

Question 19

Which of the following is a function of the hypothalamic-hypophyseal portal system?

Accepted Answer

It carries releasing and inhibiting hormones from the hypothalamus to the anterior pituitary.

The Endocrine System: Structure, Function, and Major Hormones

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