Q: Which of the following equations correctly represents the conversion of ATP to cAMP in the second-messenger system?

$$\mathrm{ATP} \xrightarrow{\text{adenylate cyclase}} \mathrm{cAMP} + \mathrm{PP_i}$$

Question 1

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

Accepted Answer

The nervous system initiates responses rapidly and has short-duration responses, while the endocrine system initiates responses slowly and has long-duration responses.

Question 2

A patient presents with symptoms of dehydration and excessive urination. Laboratory tests reveal low levels of antidiuretic hormone (ADH). Which condition is most likely responsible for these symptoms?

Accepted Answer

Diabetes insipidus

Question 3

Which of the following hormones is produced by the anterior pituitary and stimulates the adrenal cortex to release corticosteroids?

Accepted Answer

Adrenocorticotropic hormone (ACTH)

Question 4

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

Accepted Answer

Only cells with the appropriate receptors for that hormone can respond.

Question 5

Which of the following is a correct sequence of events in the cAMP second-messenger system?

Accepted Answer

Hormone binds receptor → G protein activated → Adenylate cyclase converts ATP to cAMP → cAMP activates protein kinases

Question 6

Amino acid–based hormones (except thyroid hormone) exert their effects through which of the following mechanisms?

Accepted Answer

Second-messenger systems such as cAMP or PIP2-calcium

Question 7

Which of the following is an example of a humoral stimulus for hormone release?

Accepted Answer

Low blood calcium levels stimulating parathyroid hormone (PTH) release

Question 8

Which hormone is released in response to neural stimuli from the sympathetic nervous system?

Accepted Answer

Epinephrine from the adrenal medulla

Question 9

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

Accepted Answer

They bind to intracellular receptors and directly activate genes.

Question 10

A patient with persistently high levels of a hormone begins to lose sensitivity to that hormone. Which process best explains this phenomenon?

Accepted Answer

Down-regulation of receptors

Question 11

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

Accepted Answer

Insulin and glucagon acting on blood glucose levels

Question 12

Which of the following equations correctly represents the conversion of ATP to cAMP in the second-messenger system?

Accepted Answer

$$\mathrm{ATP} \xrightarrow{	ext{adenylate cyclase}} \mathrm{cAMP} + \mathrm{PP_i}$$

Question 13

Which hormone is released by the posterior pituitary and acts as a strong stimulant of uterine contractions during childbirth?

Accepted Answer

Oxytocin

Question 14

Which of the following best describes the feedback mechanism controlling most hormone release?

Accepted Answer

Negative feedback

Question 15

A patient with an anterior pituitary tumor is found to have enlarged hands, feet, and face. Which hormone is most likely hypersecreted?

Accepted Answer

Growth hormone (GH)

Question 16

Which of the following is a tropic hormone produced by the anterior pituitary that stimulates the thyroid gland?

Accepted Answer

Thyroid-stimulating hormone (TSH)

Question 17

Which of the following best explains why steroid hormones generally have longer half-lives than peptide hormones?

Accepted Answer

Steroid hormones are bound to plasma proteins in the blood.

Question 18

Which hormone is responsible for stimulating the production of gametes (egg or sperm) in the gonads?

Accepted Answer

Follicle-stimulating hormone (FSH)

Question 19

Which of the following is a direct metabolic effect of growth hormone (GH)?

Accepted Answer

Decreases rate of cellular glucose uptake and metabolism

Question 20

Which of the following best describes the role of the hypothalamus in regulating anterior pituitary hormone secretion?

Accepted Answer

It secretes releasing and inhibiting hormones into the hypophyseal portal system to regulate the anterior pituitary.

The Endocrine System: Structure, Function, and Regulation

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