16. The Endocrine System

Which hormone is derived from tryptophan and helps regulate circadian rhythm?

What four cell populations make up the endocrine pancreas? Which hormone does each type of cell produce?

What effects does parathyroid hormone have on blood calcium level?

Decreased blood calcium level would result in increased:

(a) Secretion of calcitonin

(b) Secretion of PTH

(c) Elimination of calcium by the kidneys

(d) Osteoclast activity

(e) Excitability of neural membranes

Julie is pregnant but is not receiving prenatal care. She has a poor diet consisting mostly of fast food. She drinks no milk, preferring colas instead. How would this situation affect Julie's parathyroid hormone level?

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

The pancreas, thyroid gland, and parathyroid glands secrete neurohormones.

Aaron, a 42-year-old single father, goes to his physician complaining of nausea and chronic fatigue. He reports having felt fatigued and listless for about half a year, but he had attributed this to stress. He has lost considerable weight and, strangely, his skin looks tanned, even though he spends long hours at work and rarely ventures outside. His doctor finds very low blood pressure and a rapid, weak pulse. Blood tests show that Aaron does not have anemia, but his plasma glucose, cortisol, and Na⁺ are low, and his plasma K⁺ is high. His doctor orders an ACTH stimulation test, in which Aaron's secretion of cortisol is measured after he is given a synthetic form of ACTH.

(a) What would account for Aaron's low plasma Na⁺ and high plasma K⁺ ?

(b) What is the reason for doing an ACTH stimulation test?

(c) Which gland is primarily affected if ACTH does not cause a normal elevation of cortisol secretion? What is this abnormality called?

(d) Which gland is primarily affected if ACTH does cause an elevation of cortisol secretion?

Endemic goiter is not really the result of a malfunctioning thyroid gland. What does cause it?

Absence of thyroid hormone would result in:

a. Increased heart rate and increased force of heart contraction

b. Depression of the CNS and lethargy

c. Exophthalmos

d. High metabolic rate

Parathyroid hormone:

a. Increases bone formation and lowers blood calcium levels

b. Increases calcium excretion from the body

c. Decreases calcium absorption from the gut

d. Demineralizes bone and raises blood calcium levels

Mary Morgan has just been brought into the emergency room of City General Hospital. She is perspiring profusely and is breathing rapidly and irregularly. Her breath smells like acetone (sweet and fruity), and her blood glucose tests out at 650 mg/100 ml of blood. She is in acidosis. Which hormone drug should be administered, and why?

Describe the body location of each of the following endocrine organs: anterior pituitary, pineal gland, pancreas, ovaries, testes, and adrenal glands.

List the hormones produced by each organ.

How are the hyperglycemia and lipidemia of insulin deficiency linked?

If there is adequate carbohydrate intake, secretion of insulin results in:

a. Lower blood glucose levels

b. Increased cell utilization of glucose

c. Storage of glycogen

d. All of these

A hormone not involved in glucose metabolism is:

a. Glucagon

b. Cortisone

c. Aldosterone

d. Insulin