Question 1

Which of the following best describes a key difference between the nervous system and the endocrine system?

Accepted Answer

The nervous system acts at specific locations determined by axon pathways, while the endocrine system acts at diffuse locations where blood reaches.

Question 2

A patient is experiencing symptoms of excessive thirst and frequent urination. Laboratory tests reveal low levels of antidiuretic hormone (ADH). Which organ is most likely malfunctioning?

Accepted Answer

Posterior pituitary gland

Question 3

Which of the following is TRUE regarding hormone receptor specificity?

Accepted Answer

A cell will only respond to a hormone if it has a receptor for that hormone.

Question 4

Which feedback mechanism is responsible for amplifying the original stimulus, such as during childbirth?

Accepted Answer

Positive feedback

Question 5

A water-soluble hormone binds to its receptor on the cell membrane. What is the next step in the second messenger pathway?

Accepted Answer

Activation of a G protein

Question 6

Which equation correctly represents the calculation of hormone half-life?

Accepted Answer

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

Question 7

Which hormone is primarily responsible for increasing blood calcium levels?

Accepted Answer

Parathyroid hormone (PTH)

Question 8

A patient with Cushing's syndrome is likely to have excess levels of which hormone?

Accepted Answer

Glucocorticoids

Question 9

Which of the following best explains why steroid hormones can activate specific genes?

Accepted Answer

Steroid hormones are lipid-soluble and bind to intracellular receptors that directly interact with DNA.

Question 10

Which of the following is NOT a major endocrine organ?

Accepted Answer

Sebaceous gland

Question 11

Which hormone is secreted by the pineal gland and helps regulate circadian rhythms?

Accepted Answer

Melatonin

Question 12

Which of the following is a correct example of antagonism in hormone interactions?

Accepted Answer

Insulin lowers blood glucose while glucagon raises it.

Question 13

Which of the following factors does NOT influence activation of a target cell by a hormone?

Accepted Answer

The organ that produced the hormone

Question 14

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

Accepted Answer

It produces hormones that are stored and released by the posterior pituitary.

Question 15

A patient is found to have low blood sodium and high blood potassium. Which hormone is most likely deficient?

Accepted Answer

Aldosterone

Question 16

Which of the following is a correct sequence in the cAMP second messenger pathway?

Accepted Answer

Hormone binds receptor $$\rightarrow G $$protein activated $$\rightarrow$$ Adenylate cyclase activated $$\rightarrow$$ cAMP produced

Question 17

Which of the following is a function of parathyroid hormone (PTH)?

Accepted Answer

Increases blood calcium by stimulating osteoclasts

Question 18

Which of the following best describes the effect of insulin?

Accepted Answer

Lowers blood glucose levels

Question 19

Which of the following is a correct example of a hormone acting through direct gene activation?

Accepted Answer

Cortisol enters the cell and binds to an intracellular receptor, which then interacts with DNA to regulate gene transcription.

Question 20

Which of the following best explains why hormones like thyroid hormone circulate bound to plasma proteins?

Accepted Answer

They are lipid-soluble and need carriers to remain soluble in blood.

The Endocrine System: Structure, Function, and Regulation

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