$$Response \propto [Hormone] \times [Receptor]$$

Question 1

Which of the following best defines a hormone?

Accepted Answer

A chemical messenger secreted by specialized epithelial cells that travels in the blood to distant target organs and acts at very low concentrations.

Question 2

Which characteristic is essential for a molecule to be classified as a hormone?

Accepted Answer

It must be secreted into the blood and act on distant targets.

Question 3

Hormones require which of the following to exert their effects on target cells?

Accepted Answer

Appropriate receptors on the target cell membrane or inside the cell.

Question 4

Which of the following is NOT a function of hormones?

Accepted Answer

Initiating muscle contraction via action potentials.

Question 5

Why do hormones act only on specific target tissues?

Accepted Answer

Only target tissues have the appropriate receptors for the hormone.

Question 6

Which of the following best describes the concentration at which hormones typically act?

Accepted Answer

Very low concentrations, often in the nanomolar ($$10^{-9} M) to $$picomolar ($$10^{-12} M) $$range.

Question 7

A patient has a mutation that prevents the expression of a specific hormone receptor on their kidney cells. What is the most likely consequence?

Accepted Answer

The hormone will not elicit a response in the kidney, even if present in the blood.

Question 8

Which of the following statements about hormone transport is correct?

Accepted Answer

Hormones are secreted into the blood and distributed throughout the entire body.

Question 9

Which of the following scenarios best illustrates the concept of hormone specificity?

Accepted Answer

Insulin acts only on cells with insulin receptors, such as muscle and adipose tissue.

Question 10

Which equation best represents the relationship between hormone concentration and response in target cells?

Accepted Answer

$$Response \propto [Hormone] 	imes [Receptor]$$

Question 11

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

Accepted Answer

Initiation of a cellular response such as gene expression or protein activation.

Question 12

Which process is necessary to terminate hormone action in the body?

Accepted Answer

Degradation by enzymes in the liver and kidneys.

Question 13

What is the primary function of the endocrine system as described in the study materials?

Accepted Answer

To maintain homeostasis through communication between cells using hormones.

Question 14

Which of the following is NOT a characteristic of hormones?

Accepted Answer

They are required in high concentrations to be effective.

Question 15

A hormone is secreted into the blood but does not cause a response in the liver. What is the most likely explanation?

Accepted Answer

Liver cells lack the specific receptor for that hormone.

Question 16

Which of the following best describes the role of hormones in growth and development?

Accepted Answer

Hormones regulate cellular processes that control growth, differentiation, and maturation.

Question 17

Which statement about hormone concentration is correct?

Accepted Answer

Even picomolar ($$10^{-12} M) $$concentrations of hormones can trigger a cellular response.

Question 18

Which of the following is a real-world example of hormone action?

Accepted Answer

Insulin released from the pancreas lowers blood glucose by acting on muscle and adipose tissue.

Endocrine Physiology: Introduction to Hormones

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