Calcium Homestasis Flashcards Preview

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Flashcards in Calcium Homestasis Deck (18):

How does calcium affect muscle contraction

Decreases calcium in ECF which is free
Increases sodium perm
Depolarises Em closer to threshold


What are the results of a muscle spasm

Spontaneous contraction of RESP muscle can lead to asphyxiation


What dos calcium have to do with excitation contraction of cardiac and skeletal muscle

Action potential increase calcium perm
Entry of ECF calcium to cardiac and skeletal muscle cells trigger contractile mechanism


What dos calcium do in stumulus sec coupling

Secretory cells - increased calcium perm on repsonse to stimulus increases calcium entry - triggers release by exocytosis
Sec neurotransmitters, peptide hormones


How does calcium affect blood clotting

Acts as a co factor


What hormones as associated with calcium balance

Parathyroid hormone - raises plasma conc calcium

Calcitonin - lowers plasma conc calcium

Vitamin D3 - active form promotes calcium abs in gut

Growth hormone - favours increase bone mass


Which hormone used for calcium balance is essential for life

Parathyroid hormone


How is PTH stored

As pre or prepro hormone


What is the target for PTH

Kidney and bone


What cells prod PTH

Chief cells of parathyroid glands


What su the action of PTH

Hyper alchemical raises plasma conc calcium


What is the normal range of calcium plasm aconc

Between 2-2.5


What are e actions of PTH

Stimulates osteoclasts - promote bone resorb mobilise calcium and phosphate

Increases renal calcium abs

Decreases renal Phosohate reabs

Stimulate kidneys to conv vit d to active calcitriol to increase abs of calcium form but


What is calcitonin

Peptide form paragoliicilar cells of thyroid
Relaease in response to rising plasma calcium
Not ,UCP function though to help in pregnancy


What happens if PTH is low

Increased nerve excitability
Lead to death asphyxiation
Lowered calcium plasma concentration

Treat - infuse calcium and give vit d metabolites


What is PTH is too high

Tumours of parathyroid glands
Lead to bone demineralisation kidney stones filtered load of calcium high
Reduction in inhib effect of osteoporosis s


What is vit d def

Rickets shifted bones in children
Osteomalacia in adults bone density decreases


What is the role of calcium

Bone and teeth integrity
Muscle contraction
Mem stability
Neurotransmitter release
Secretory processes
Enzyme reg