Question 1

Which of the following best describes the mechanism by which steroid hormones exert their effects on target cells?

Accepted Answer

They bind to cytosolic or nuclear receptors and alter gene transcription.

Question 2

A patient receives an injection of insulin. Which property of insulin explains why it must be injected rather than taken orally?

Accepted Answer

Insulin is a peptide hormone and would be digested in the gastrointestinal tract.

Question 3

Which hormone class is most likely to have a long half-life in the bloodstream?

Accepted Answer

Steroid hormones, because they are bound to carrier proteins.

Question 4

Which of the following is an example of a permissive effect in hormone interactions?

Accepted Answer

Estrogen making the uterus more responsive to progesterone.

Question 5

A hydrophilic hormone binds to its receptor on the plasma membrane. What is the most likely immediate cellular response?

Accepted Answer

Opening or closing of ion channels and activation of second messenger pathways.

Question 6

Which of the following hormones is derived from cholesterol?

Accepted Answer

Testosterone

Question 7

A patient has elevated blood glucose levels. Which hormone is most likely to be secreted in response, and what is the mechanism of its release?

Accepted Answer

Insulin, released by exocytosis from beta cells.

Question 8

Which of the following best explains why exposure to high concentrations of a hormone can lead to down-regulation?

Accepted Answer

Target cells decrease the number of receptors to reduce responsiveness.

Question 9

Which equation correctly represents the half-life ($$t_{1/2}) of a $$hormone in plasma?

Accepted Answer

$$t_{1/2} = \frac{0.693}{k}$$, where $$k is $$the rate constant for removal

Question 10

Which of the following is a property of lipophobic (hydrophilic) hormones?

Accepted Answer

They are stored in secretory vesicles and released by exocytosis.

Question 11

A patient is given a drug that blocks G protein-coupled receptors. Which hormone's action would be most affected?

Accepted Answer

Epinephrine

Question 12

Which of the following hormones is most likely to require a carrier protein for transport in the blood?

Accepted Answer

Cortisol

Question 13

Which of the following is an example of antagonistic hormone interaction?

Accepted Answer

Insulin and glucagon regulating blood glucose levels.

Question 14

Which property distinguishes peptide hormones from steroid hormones?

Accepted Answer

Peptide hormones are hydrophilic and bind to plasma membrane receptors.

Question 15

Which of the following best describes the process of up-regulation in hormone signaling?

Accepted Answer

Target cells increase the number of receptors to enhance sensitivity to a hormone.

Question 16

Which hormone is most likely to activate gene transcription after binding to its receptor?

Accepted Answer

Cortisol

Question 17

A patient with a deficiency in carrier proteins would most likely have altered levels of which hormone?

Accepted Answer

Testosterone

Question 18

Which of the following is a direct effect of a hydrophilic hormone binding to its receptor?

Accepted Answer

Activation of membrane-bound enzymes via second messengers.

Question 19

Which hormone is most likely to be released in response to a decrease in blood calcium levels?

Accepted Answer

Parathyroid hormone (PTH)

Question 20

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

Accepted Answer

Steroid hormones are bound to carrier proteins, protecting them from rapid removal.

Endocrine System: Structure, Function, and Hormone Classification

Study Guide - Practice Questions