Basic Calcium Homeostasis(Physiology)

Question 1

where are calcium-sensing receptors(CASR) found

Answer 1

in the parathyroids

Question 2

what type of receptor is the calcium-sensing receptor(CASR)

Answer 2

G protein coupled receptor

Question 3

describe what contributes to increased serum Ca2+

Answer 3

Ca2+ gut absorption, increased Ca2+ kidney reabsorption, increased Ca2+ bone resorption

Question 4

what effect does kidney 1,25-(OH)2 vitamin D have on Ca2+ gut absorption

Answer 4

increased kidney vitamin D results in Ca2+ gut absorption

Question 5

what affect does parathyroid hormone(PTH) have on Ca2+ homeostasis and on vitamin D

Answer 5

it increases kidney reabsorption of Ca2+ and bone resorption of Ca2+
also increases kidney 1,25(OH)2 vitamin D
(which all result in increased serum Ca2+)

Question 6

what happens at the parathyroid when there is high serum Ca2+

Answer 6

Ca2+ binds to the calcium-sensing receptors

Question 7

what effect does serum Ca2+ binding to the calcium-sensing receptors have on parathyroid secretion

Answer 7

results negative feedback loop inhibiting PTH secretion, as PTH secretion increases serum Ca2+