Chapter 21: Mechanisms of Hormonal Regulation

Question 1

What is calcitonin and what does it do?

Answer 1

Also called thyrocalcitonin, it acts to lower serum calcium levels by inhibition of bone-resorbing osteoclasts.
(p. 702)

Question 2

Two pairs of parathyroid glands normally are present, but the number may range from…

Answer 2

…two to six.

p. 702

Question 3

The parathyroid glands produce parathyroid hormone (PTH), which…

Answer 3

…works in concert with vitamin D to increase serum calcium concentration.
(p. 702)

Question 4

The overall effect of PTH is to…

Answer 4

…increase serum calcium and decrease serum phosphate.

p. 702

Question 5

What is procalcitonin?

Answer 5

It is a precursor molecule to calcitonin. It’s a stress hormone that is elevated in infectious and inflammatory disorders.
(p. 702)

Question 6

Where is calcitonin produced?

Answer 6

In the tissue of the thyroid, by parafollicular cells called C cells.
(p. 702)