Question 1

Which of the following best explains why the effects of hormones released by the endocrine system can be long-lasting compared to neurotransmitters released by the nervous system?

Accepted Answer

Hormones are released into the bloodstream, allowing them to reach distant targets and persist longer due to slower degradation.

Question 2

A patient is diagnosed with a deficiency in a liver-produced protein that binds steroid hormones in the blood. Which of the following is the most likely consequence?

Accepted Answer

Decreased biological half-life of steroid hormones, leading to reduced hormone levels in the blood.

Question 3

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

Accepted Answer

They bind to plasma membrane receptors, activating second messenger systems such as cAMP or IP3.

Question 4

A researcher discovers a new hormone that is synthesized from cholesterol, is lipid-soluble, and binds to intracellular receptors. Which category does this hormone most likely belong to?

Accepted Answer

Steroid hormone

Question 5

Which of the following is a correct sequence of events for the adenylate cyclase pathway activated by a water-soluble hormone?

Accepted Answer

Hormone binds receptor → G-protein activated → ATP converted to cAMP → Protein Kinase A activated

Question 6

A patient is experiencing increased pain sensitivity, fever, and inflammation. Which local hormone is most likely involved in mediating these symptoms?

Accepted Answer

Prostaglandin

Question 7

Which of the following best illustrates a permissive hormone interaction?

Accepted Answer

Thyroid hormone is required for the full effect of growth hormone on bone development.

Question 8

Which of the following statements about hormone elimination is correct?

Accepted Answer

Hormone elimination occurs primarily through enzymatic degradation in the liver, renal excretion, or uptake by target cells.

Question 9

A cell increases the number of receptors for a particular hormone in response to low hormone levels. This process is known as:

Accepted Answer

Up-regulation

Question 10

Which of the following is a key advantage of signal transduction cascades initiated by water-soluble hormones?

Accepted Answer

They allow for amplification of the hormonal signal and multiple points of regulation.

Question 11

A patient is given a drug that inhibits phospholipase C. Which of the following effects would most likely be observed?

Accepted Answer

Decreased production of diacylglycerol (DAG) and inositol triphosphate (IP3), leading to reduced activation of Protein Kinase C and lower intracellular calcium.

Question 12

Which of the following best describes the difference between autocrine and paracrine signaling by local hormones?

Accepted Answer

Autocrine signaling affects the cell that released the hormone, while paracrine signaling affects neighboring cells.

Question 13

Which of the following is NOT considered a major endocrine organ?

Accepted Answer

Liver

Question 14

A water-soluble hormone binds to its receptor and activates a G-protein. Which of the following best describes the next step in the signal transduction pathway?

Accepted Answer

The G-protein exchanges GDP for GTP and activates an effector enzyme such as adenylate cyclase or phospholipase C.

Question 15

Which of the following hormones is lipid-soluble but is NOT a steroid?

Accepted Answer

Thyroid hormone

Question 16

A patient with a genetic mutation that prevents the synthesis of G-proteins would most likely have impaired responses to which type of hormone?

Accepted Answer

Water-soluble hormones

Question 17

Which of the following best describes the antagonistic interaction between hormones?

Accepted Answer

One hormone opposes the action of another hormone.

Question 18

Which of the following is a function of prostaglandins as local hormones?

Accepted Answer

Stimulate the hypothalamus to raise body temperature and promote inflammation.

Question 19

Which of the following best explains why water-soluble hormones generally have shorter half-lives than lipid-soluble hormones?

Accepted Answer

Water-soluble hormones are rapidly degraded and eliminated because they are not protected by transport proteins.

Question 20

A patient is found to have excessive activation of Protein Kinase C in their cells. Which signaling pathway is most likely overactive?

Accepted Answer

Phospholipase C pathway

The Endocrine System: Structure, Function, and Hormone Action

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