Question 1

Which of the following best describes up-regulation of hormone receptors?

Accepted Answer

Target cells form more receptors in response to low hormone levels in the blood.

Question 2

A patient is given a drug that causes down-regulation of insulin receptors. What is the most likely effect on the patient's response to insulin?

Accepted Answer

The patient's cells will become less sensitive to insulin.

Question 3

Which hormone interaction is exemplified when progesterone down-regulates estrogen receptors in the uterus during pregnancy?

Accepted Answer

Antagonism

Question 4

If the half-life of testosterone is 12 days, how much of the original hormone remains after 36 days?

Accepted Answer

$$\frac{1}{8}$$

Question 5

Which of the following statements about lipid-soluble hormones is TRUE?

Accepted Answer

They are bound by plasma proteins and often require metabolism by the liver before excretion.

Question 6

A researcher finds that a hormone's effect on a target cell is amplified when another hormone is present, and the combined effect is greater than the sum of their individual effects. This is an example of:

Accepted Answer

Synergism

Question 7

Which process best explains why a cell exposed to persistently high levels of a hormone may become less responsive to that hormone?

Accepted Answer

Down-regulation of receptors

Question 8

If a hormone has a half-life of 6 hours, how long will it take for its concentration to decrease to $$\frac{1}{16} of $$its original value?

Accepted Answer

$$24$$ hours

Question 9

Which organ is primarily responsible for metabolizing lipid-soluble hormones before they are excreted?

Accepted Answer

Liver

Question 10

A patient with low blood levels of a hormone is found to have increased receptor density on target cells. This is most likely due to:

Accepted Answer

Up-regulation

Question 11

Which of the following best describes the effect of up-regulation on cell sensitivity to a hormone?

Accepted Answer

Increased receptor density and stronger response

Question 12

A hormone is found to be removed from the blood primarily by degrading enzymes. What does this suggest about the hormone's solubility?

Accepted Answer

It is likely water-soluble.

Question 13

If the initial concentration of a hormone is $$100$$ units and its half-life is $$10$$ hours, what will its concentration be after $$30$$ hours?

Accepted Answer

$$12.5$$ units

Question 14

Which of the following is an example of a hormone interaction where one hormone requires another to be present for full effect?

Accepted Answer

Permissiveness

Question 15

A cell exposed to high levels of estrogen increases its number of progesterone receptors. This is an example of:

Accepted Answer

Up-regulation by another hormone

Question 16

Which of the following is NOT a typical mechanism for hormone removal from the blood?

Accepted Answer

Binding to plasma proteins

Question 17

A hormone with a half-life of $$1$$ day is administered to a patient. After $$3$$ days, what fraction of the original hormone remains?

Accepted Answer

$$\frac{1}{8}$$

Question 18

Which of the following would most likely result in diminished cellular response to a hormone?

Accepted Answer

Down-regulation of hormone receptors

Question 19

If a hormone is water-soluble, which of the following is most likely TRUE about its half-life?

Accepted Answer

It is shorter than that of lipid-soluble hormones.

Question 20

A cell exposed to persistently low hormone levels increases its receptor density. What is the physiological term for this process?

Accepted Answer

Up-regulation

Hormone Regulation and Activity: Target Cell Sensitivity and Hormone Half-Life

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