Calcium homeostasis Flashcards
what does a decrease in Ca lead to
severe hypocalcaemia = muscle spasm
hormones involved in calcium homeostasis
parathyroid hormone (PTH)
1,25 dihydroxy vitamin D
calcitonin
what hormone is released when calcium levels are low
parathyroid hormone
what is prevented when there is high calcium levels in blood
parathyroid hormone release
how does the parathyroid hormone effect the kidneys
stimulates renal calcium reabsorption and inhibits renal phosphate reabsorption
stimulates synthesis of 1,25 dihydroxyvit D
how does the parathyroid hormone affect bone
promotes resorption OR deposition
what cells action bone resorption
osteoclasts
what cells action bone deposition
osteoclasts
where is 1,25 dihydroxyvitD synthesised
kidney
action of 1,25dVitD
raise plasma concentration of calcium and phosphate
consequences of vit D def
impaired intestinal absorption of calcium = hypocalcemia
increased PTH secretion
increased bone resorption = soft and deformed bones
what disease is caused by vit D def in children
rickets
what disease is caused by vit D def in adults
osteomalacia
where is calcitonin released
thyroid gland
what triggers the release of calcitonin from the thyroid gland
extracellular calcium
