Parathyroid gland and calcium homeostasis Flashcards
what do chief cells produce
parathyroid hormone
what do oxyphilic cells do
unknown function
what is the function of parathyroid hormone
increases plasma calcium conc
what is the function of calcitonin
decreases plasma calcium conc
what are the functions of calcium
prosthetic group for enzymes and structural proteins
involved in sodium channel
excitation contraction coupling in muscles
excitation secretion coupling at axonal terminals and glands
blood coagulation
intracellular second messenger
describe the control of parathyroid hormone release
chief cells in the parathyroid detect increasing calcium levels which inhibits synthesis and release of PTH
mediated by activation of the Gq G-protein coupled cascade through the action of phospholipase C.
where is calcium found in the body
bones, teeth, muscles, intracellular
where is calcitonin made
parafollicular cells (C cells) of the thyroid gland
what cells are responsible for the destruction of bone and are therefore responsive to PTH
osteoclasts
what is the effect of PTH on vitamin D
converts 25-hydroxycholecalciferol, the major circulating form of inactive vitamin D, into 1,25-dihydroxycholecalciferol, the active form of vitamin D, in the kidney.
what is the effect of PTH on phosphate
reduces reabsorption of phosphate from the proximal tubules of the kidney, so more phosphate is excreted
what vitamin is needed for absorption of calcium and phosphate from the intestine
vit D
what is ergocalciferol
vit D2
what is cholecalciferol
Vit D3
what is phosphate needed for
build and repair bones and teeth, help nerves function, and make muscles contract.
