Question 1

Which of the following best describes the primary difference between the endocrine and nervous systems in terms of response time and duration?

Accepted Answer

The nervous system responds rapidly with short-lasting effects, while the endocrine system responds slowly with long-lasting effects.

Question 2

A patient presents with persistently high levels of a hormone. Which regulatory mechanism is most likely to occur in their target cells?

Accepted Answer

Down-regulation, resulting in decreased receptor numbers.

Question 3

Which of the following hormones is most likely to act via a second messenger system involving cyclic AMP ($$cAMP$$)?

Accepted Answer

Epinephrine

Question 4

What is the correct sequence of events for a water-soluble hormone acting on a target cell?

Accepted Answer

Hormone binds to plasma membrane receptor, activates second messenger, triggers cellular response.

Question 5

Which equation correctly represents the formation of cyclic AMP ($$cAMP) $$from ATP?

Accepted Answer

$$ATP \xrightarrow{Adenylate\ Cyclase} cAMP + PP_i$$

Question 6

A hormone is classified as lipid-soluble. Which of the following is TRUE regarding its mechanism of action?

Accepted Answer

It diffuses through the plasma membrane and binds to intracellular receptors to directly activate gene transcription.

Question 7

Which of the following best explains why only certain cells respond to a specific hormone?

Accepted Answer

Target cells must have specific receptors for the hormone.

Question 8

Which of the following is NOT a major function regulated by the endocrine system?

Accepted Answer

Initiation of voluntary muscle contraction

Question 9

A patient is given a drug that inhibits phosphodiesterase. What is the expected effect on $$cAMP$$ levels in their cells?

Accepted Answer

$$cAMP$$ levels will increase due to reduced degradation.

Question 10

Which of the following best describes the role of the hypothalamus in endocrine regulation?

Accepted Answer

It controls release of hormones from the pituitary gland via neural and hormonal signals.

Question 11

Which of the following is a correct example of negative feedback in endocrine regulation?

Accepted Answer

Elevated thyroid hormone levels inhibit further release of TSH from the anterior pituitary.

Question 12

Which of the following is TRUE regarding the half-life of hormones?

Accepted Answer

Lipid-soluble hormones are usually bound to plasma proteins and have longer half-lives.

Question 13

Which of the following best describes the hypophyseal portal system?

Accepted Answer

A network of blood vessels connecting the hypothalamus to the anterior pituitary, allowing direct hormone transport.

Question 14

Which of the following hormones is secreted by the anterior pituitary and regulates growth?

Accepted Answer

Growth hormone (GH)

Question 15

A patient with a tumor in the adrenal cortex is found to have elevated ACTH levels. Which feedback mechanism is most likely disrupted?

Accepted Answer

Negative feedback from cortisol to the anterior pituitary and hypothalamus

Question 16

Which of the following is a correct pathway for hormone release involving the hypothalamus and anterior pituitary?

Accepted Answer

Hypothalamus releases releasing hormones into portal vessels, which stimulate the anterior pituitary to secrete tropic hormones.

Question 17

Which of the following is NOT a peptide hormone secreted by the anterior pituitary?

Accepted Answer

Thyroid hormone (TH)

Question 18

Which of the following best describes the effect of up-regulation in target cells?

Accepted Answer

Target cells increase the number of hormone receptors in response to low hormone levels.

Question 19

Which of the following is a correct example of a tropic hormone?

Accepted Answer

Thyroid-stimulating hormone (TSH)

Question 20

Which of the following best explains why steroid hormones have a delayed onset of action compared to peptide hormones?

Accepted Answer

Steroid hormones must diffuse into the cell and initiate gene transcription, which takes longer than activating second messenger systems.

Introduction to the Endocrine System – ANP 1105A Study Notes

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