16. The Endocrine System

What four conditions cause the release of erythropoietin?

In what ways can a hormone modify the activities of its target cells?

Which type of hormone receptor—plasma membrane bound or intracellular—would be expected to provide the most long-lived response to hormone binding and why?

In Type 2 diabetes, insulin levels are frequently normal, yet the target cells are less sensitive to the effects of insulin. This suggests that the target cells:

(a) Are impermeable to insulin

(b) May lack enough insulin receptors

(c) Cannot convert insulin to an active form

(d) Have adequate internal supplies of glucose

(e) Both b and c

Roger has been extremely thirsty. He drinks numerous glasses of water every day and urinates a great deal. Name two disorders that could produce these signs and symptoms. What test could a clinician perform to determine which disorder Roger has?

Pamela and her teammates are considering taking anabolic steroids (synthetic hormones derived from testosterone) to enhance their competitive skills. What natural effects of testosterone are they hoping to gain? What additional side effects might these women expect should they begin an anabolic steroid regime?

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

The cells of the nervous system communicate via action potentials, whereas the cells of the endocrine system communicate via hormones.

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

Steroid hormones are hydrophilic molecules that bind to plasma membrane proteins as part of a second-messenger system.

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

The secretion of most hormones is regulated by a negative feedback system.

Which of the following is not a potential effect that a hormone could have on its target cell?

a. Activating genes in the DNA

b. Stimulating cellular division

c. Altering the permeability of the plasma membrane

d. All of the above are potential effects of a hormone on its target cell.

How does ADH affect the amount of water in the body, and how does it accomplish this? How does this affect the osmolarity of the blood?

List the target tissues and effects of the following anterior pituitary gland hormones.

a. Thyroid-stimulating hormone

b. Adrenocorticotropic hormone

c. Prolactin

d. Gonadotropins

e. Growth hormone

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

About 90% of the thyroid hormone produced is triiodothyronine (T3).

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

Thyroxine (T4) is the more active of the two thyroid hormone

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

Iodine atoms are a key component of parathyroid hormone.