Calcium and phosphate metabolism

Question 1

What cells release PTH?

Answer 1

Chief cells

Question 2

What triggers PTH release?

Answer 2

Low serum calcium

Question 3

What are the actions of PTH?

Answer 3

Increases calcium absorption in the intestine by increasing calcitriol, increasing bone resorption, decreases phosphate reabsorption, increases calcium reabsorption

Question 4

What is the main way of controlling calcium levels?

Answer 4

PTH

Question 5

What cells release calcitonin?

Answer 5

Parafollicular cells

Question 6

What triggers release of calcitonin?

Answer 6

High serum calcium

Question 7

What is the action of calcitonin?

Answer 7

Decreases bone resorption to decrease serum calcium

Question 8

What triggers FGF-23 release?

Answer 8

High serum phosphate, high serum PTH, high serum calcitriol, dietary phosphate loading

Question 9

What cells release FGF-23?

Answer 9

Osteocytes

Question 10

What is the action of FGF-23?

Answer 10

Decreasing 1-alpha-hydroxylation of vitamin D which decreases gut absorption of phosphate and decreases expression of Na transporter in the renal tubule which increases renal phosphate excretion

Question 11

What is klotho transmembrane protein associated with?

Answer 11

FGF-23

Question 12

What is the precursor to vitamin D?

Answer 12

7-Dehydrocholesterol

Question 13

What is calcitriol?

Answer 13

Activated vitamin D