calcium regulation Flashcards
calcium function
NT and horomone release, muscle contraction, second messanger, bone
* alters nerve activity
hypocalcemia
increased nerve excitibility –>muscle tetany –> death
is calcium tightly or loosely regulated
tightly
osteoblasts
bone deposition
decrease plasma Ca++
largely not regulated
osteoclasts
bone resorption
increase plasma Ca++
regulated
calcitonin inhibits
osteoclasts
parathyroid hormone (PTH) stimualtes
osteoclasts
PTH increases
- plasma Ca++
- resorption (bone)
- reabsorption (kidney)
- absorption (GI)
what type of hormone is PTH
peptide
what does PTH stimulate that increases absorption in GI
vitamin D3
what happens if both Ca++ and PO4 are increased
precipitate (crystals)
where is calcitonin made
parafollicular cells in thyroid gland
what type of hormone is calcitonin
peptide
high plasma Ca++ causes the release of
calcitonin
calcitonin causes decrease in
resorption
absorption
readsorption
where is vitamin D3 made
kidneys
what type of hormone is vitamin D3
steroid
active vitamin D3 causes an increase in
- resorption
- absorption
- reabsorption
- INCREASED PLASMA CA++
decrease in plasma Ca++ means an increase in
plasma PO4
osteoporosis
loss of bone, greater problem in women than in men (menopause)
rickets
lack of active Vit D3 in children
osteomalacia
lack of active Vit D3 in adults
cause of rickets and osteomalacia
lack of vitamin D3 in the diet AND sunlight, or liver/kidney damage
a decrease in both plasma Ca++ and PO4 causes
poor mineralerizaiton
reduced bone strength
