16. The Endocrine System

A rise in free T3 and T4 would be expected to produce a(n) ______ in TRH and TSH secretion. A decrease in free T3 and T4 would be expected to produce a(n) _____ a(n)_____in TRH and TSH secretion.

Females with hormone-secreting tumors of the adrenal cortex occasionally develop male secondary sex characteristics. Explain why this may happen.

You have read that aldosterone causes sodium ion retention from the kidneys. How would blocking aldosterone secretion decrease the amount of water retained from the fluid in the kidneys?

Identify the endocrine glands and tissues in the following diagram.

a. ___

b. ___

c. ___

d. ___

e. ___

f. ___

g. ___

h. ___

i. ___

j. ___

k. ___

l. ___

m. ___

What has likely happened to the pH of Mr. Montez's blood? What does this mean about the hydrogen ion concentration in his blood? How will his buffer systems respond to this change in pH?

Between the statements below, which one correctly describes a significant difference between how the endocrine and nervous systems function?

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

Insulin operates by activating a receptor on the outside of the target cell. Based on your knowledge of hormone types, do you expect insulin to be an amino acid-based hormone or a steroid hormone, and why?

For a nerve impulse to travel from one neuron to another, the signal must be transmitted across a synapse. At the synapse, the axon releases a neurotransmitter that then diffuses across the synapse and activates receptors on the subsequent dendrite. While this is an example of a nervous signal using a neurotransmitter, the action of neurotransmitter at a synapse is also sometimes considered an example of what other type of signaling?

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

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.

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

Which of the following is not an effect of aldosterone?

a. Increased excretion of hydrogen ions from the fluid in the kidneys

b. Increased retention of sodium ions from the fluid in the kidneys

c. Increased retention of potassium ions from the fluid in the kidneys

d. Increased retention of water from the fluid in the kidneys

Explain how insulin and glucagon are antagonists.