After 6 hours, concentration will be $$C_0$$ \times \frac{1}{$$2^3$$} = $$C_0$$ \times \frac{1}{8}$$.

Question 1

Which of the following best explains why a cell responds to a specific hormone?

Accepted Answer

The cell has a receptor for that hormone.

Question 2

What is the effect of up-regulation in hormone receptor dynamics?

Accepted Answer

Target cells increase the number of receptors for a hormone.

Question 3

Which factor does NOT directly affect the degree of target cell activation by a hormone?

Accepted Answer

The cell's metabolic rate.

Question 4

A patient is exposed to persistently high levels of a hormone. What is the most likely cellular response?

Accepted Answer

Down-regulation of receptors, leading to decreased sensitivity.

Question 5

Which hormone interaction describes the situation where one hormone cannot exert its full effects without another hormone being present?

Accepted Answer

Permissiveness

Question 6

If both glucagon and epinephrine act together on the liver, what is the expected effect?

Accepted Answer

Amplified release of glucose compared to either hormone acting alone.

Question 7

Which hormone interaction occurs when one hormone opposes the action of another?

Accepted Answer

Antagonism

Question 8

What is the primary reason lipid-soluble hormones remain in the blood longer than water-soluble hormones?

Accepted Answer

They are bound to plasma proteins and not rapidly removed by kidneys.

Question 9

Where are the receptors for lipid-soluble hormones typically located?

Accepted Answer

Inside the cell

Question 10

Which of the following is TRUE regarding water-soluble hormones?

Accepted Answer

They act through second messenger systems.

Question 11

A hormone has a half-life of 2 hours. If its initial concentration is $$C_0$$, what will its concentration be after 6 hours?

Accepted Answer

After 6 hours, concentration will be $$C_0$$ 	imes \frac{1}{$$2^3$$} = $$C_0$$ 	imes \frac{1}{8}$$.

Question 12

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

Accepted Answer

Activate genes, causing synthesis of new proteins.

Question 13

A patient with persistently low levels of a hormone is likely to experience which cellular adaptation?

Accepted Answer

Up-regulation of hormone receptors.

Question 14

Which of the following is NOT a characteristic of lipid-soluble hormones?

Accepted Answer

Stored in secretory vesicles.

Question 15

What is the most likely outcome if progesterone down-regulates estrogen receptors in the uterus?

Accepted Answer

Estrogen's actions are antagonized.

Question 16

Which of the following hormones would be expected to have the shortest half-life in blood?

Accepted Answer

Water-soluble hormones

Question 17

Which scenario best illustrates antagonism between hormones?

Accepted Answer

Insulin lowers blood glucose, while glucagon raises it.

Question 18

Which equation best represents the exponential decay of hormone concentration over time, given a half-life $$t_{1/2}$$?

Accepted Answer

C(t) = $$C_0$$ 	imes $$2^{-t/t_{1/2}$$}$

Question 19

Which of the following is a plausible reason for a hormone to be secreted in an inactive form?

Accepted Answer

It must be activated in the target cell to exert its effect.

Question 20

Which statement best describes the relationship between hormone solubility and mechanism of action?

Accepted Answer

Lipid-soluble hormones activate genes inside the cell, while water-soluble hormones act through second messenger systems.

Hormone Action and Interaction: Endocrine System Study Notes

Study Guide - Practice Questions