16. The Endocrine System

What is the primary difference in the way the nervous and endocrine systems communicate with their target cells?

List some problems that elderly people might have as a result of decreasing hormone production.

Which of the following correctly describes the functions of the endocrine system?

a. Transport of blood through the body and through the lungs

b. Regulation of body functions through hormone secretion

c. Regulation of body functions through nerve impulses

d. Immunity and returning extra tissue fluid to the blood vessels

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

Autocrine signals affect the same cells that secrete them.

Adrenocorticotropic hormone (ACTH) stimulates the release of:

(a) Thyroid hormones by the hypothalamus

(b) Gonadotropins by the adrenal glands

(c) Growth hormones by the hypothalamus

(d) Steroid hormones by the adrenal glands

A cell's hormonal sensitivities are determined by the:

(a) Chemical nature of the hormone

(b) Quantity of circulating hormone

(c) Shape of the hormone molecules

(d) Presence or absence of appropriate receptors

(e) Thickness of its plasma membrane

More than one choice may apply. In the hormone-signaling pathway represented in the figure,_________ is the first messenger, and _______is the second messenger that will signal a change in cell activity.

Explain what mechanism of hormone action is occurring in this image. How does it work? Give an example of a hormone that uses this mechanism.

What six hormones primarily affect growth?

Describe the chemical nature of hormones.

Define hormone.

Provide one example for each way endocrine glands are stimulated to release their hormones.