16. The Endocrine System

Explain how insulin and glucagon are antagonists.

Type 1 diabetes mellitus is characterized by______ , and type 2 diabetes mellitus is characterized by_____.

a. hypoglycemia; destruction of the pancreatic β cells

b. destruction of the pancreatic β cells; destruction of the pancreatic α cells

c. insulin resistance; destruction of the pancreatic β cells

d. destruction of the pancreatic β cells; insulin resistance

Match the following hormones with their correct descriptions.      

_____Leptin      

_____Atrial natriuretic peptide      

_____Melatonin      

_____Estrogens      

_____Erythropoietin      

_____Testosterone

a. Produced by the pineal gland; regulates the sleep/wake cycle

b. Produced by the kidneys; regulates red blood cell production

c. Produced by the heart; promotes sodium ion loss in the kidneys and vasodilation

d. Produced by the testes; promotes androgenic and anabolic actions

e. Produced by adipose tissue; promotes satiety

f. Produced by the ovaries; regulate the menstrual cycle and the development of secondary sex characteristics

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

a. Both ADH and aldosterone increase the amount of water in the body and decrease the solute concentration of the blood.

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

b. Thyroid hormones and insulin maintain blood glucose concentration during fasting.

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

d. Insulin secretion rises during feeding; growth hormone and glucagon are secreted during feeding if protein is present in the meal.

Predict the effects of a pancreatic tumor that secretes insulin. How would the effects change if the tumor secreted glucagon instead?

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

A new diet guru claims hypersecretion of cortisol is the reason why so many people are obese. He is marketing a dietary supplement that is supposedly able to block cortisol secretion and lead to weight loss. How would cortisol hypersecretion cause weight gain? Would blocking normal cortisol secretion lead to weight loss? Why or why not?

Let's say that the dietary supplement in question 2 actually works and successfully blocks cortisol secretion. Could this drug potentially be harmful? Predict its effects on overall homeostasis.

Mr. Montez is a patient with type I diabetes mellitus. He presents with dizziness, rapid breathing, confusion, and weakness. You find out that he forgot to inject his normal dose of insulin this morning. Will his blood glucose concentration be normal? Explain. Your colleague suggests that Mr. Montez needs to ingest some sugar. Is this going to help him? Why or why not? 

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?

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?