Q: Which equation best represents the negative feedback regulation of hormone levels?

$$\text{Increase in hormone} \rightarrow \text{Increase in target organ activity} \rightarrow \text{Decrease in hormone release}$$

Question 1

Which of the following best describes the difference in mechanism of action between water-soluble and lipid-soluble hormones?

Accepted Answer

Water-soluble hormones bind to plasma membrane receptors and activate second messenger systems, while lipid-soluble hormones bind to intracellular receptors and directly activate gene transcription.

Question 2

A patient is experiencing symptoms due to persistently high levels of a hormone. Which regulatory process is most likely occurring in their target cells?

Accepted Answer

Down-regulation, resulting in decreased receptor numbers.

Question 3

Which equation correctly represents the enzymatic conversion of ATP to cyclic AMP (cAMP) in the cAMP signaling pathway?

Accepted Answer

$$ATP \xrightarrow{adenylate\ cyclase} cAMP$$

Question 4

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

Accepted Answer

Initiation of rapid, short-duration responses to stimuli

Question 5

A hormone is released in response to low blood calcium levels. What type of stimulus is this?

Accepted Answer

Humoral stimulus

Question 6

Which of the following statements about hormone half-life is correct?

Accepted Answer

Lipid-soluble hormones are usually bound to plasma proteins, resulting in a longer half-life.

Question 7

Which of the following is a correct sequence for the mechanism of action of a steroid hormone?

Accepted Answer

Steroid hormone diffuses through plasma membrane → binds intracellular receptor → receptor-hormone complex enters nucleus → binds DNA → initiates transcription to mRNA

Question 8

Which hormone is synthesized by the paraventricular nucleus (PVN) neurons and released from the posterior pituitary?

Accepted Answer

Oxytocin

Question 9

A researcher is studying the effect of a hormone on its target cell. Which factor will NOT influence the activation of the target cell?

Accepted Answer

Concentration of plasma proteins in the blood

Question 10

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 are released into the blood and act on distant targets, while neurotransmitters act locally and are rapidly degraded.

Question 11

Which of the following hormones is NOT secreted by the anterior pituitary?

Accepted Answer

Oxytocin

Question 12

Which process is responsible for the rapid degradation of cAMP in the cell?

Accepted Answer

Phosphodiesterase

Question 13

A patient with a tumor secreting excess ACTH would most likely show increased activity in which target organ?

Accepted Answer

Adrenal cortex

Question 14

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

Accepted Answer

Thyroid-stimulating hormone (TSH)

Question 15

Which equation best represents the negative feedback regulation of hormone levels?

Accepted Answer

$$	ext{Increase in hormone} ightarrow 	ext{Increase in target organ activity} ightarrow 	ext{Decrease in hormone release}$$

Question 16

Which of the following is TRUE regarding the hypophyseal portal system?

Accepted Answer

It consists of two capillary plexuses connected by portal veins, allowing hypothalamic hormones to regulate anterior pituitary hormone secretion.

Question 17

Which of the following is a correct statement about hormone transport in the blood?

Accepted Answer

Steroid and thyroid hormones circulate bound to plasma proteins, while most other hormones circulate freely.

Question 18

Which of the following best describes the role of CREB in the cAMP signaling pathway?

Accepted Answer

CREB is a nuclear protein that binds to DNA and stimulates gene transcription in response to cAMP.

Question 19

Which of the following is NOT a direct effect of hormone binding to its target cell?

Accepted Answer

Production of antibodies

Introduction to the Endocrine System: Structure, Function, and Regulation

Study Guide - Practice Questions

Study Guide - Flashcards