Calcium Flashcards
Functions of Calcium (4)
Bone Formation
Cell Division and Growth
Muscle Contraction
Neurotransmitter Release
What happens with Calcium Metabolism between Gut and Extracellular Fluid
Secretion from Extracell to Gut
Absorption from Gut to Extracell
What happens with Calcium Metabolism between Extracell Fluid and Bone
Deposition from Bone to Extracell
Absorption from Extracell to Bone
What happens with Calcium Metabolism between Kidneys and Extracell Fluid
Filtration and Reabsorption
How much Calcium is metabolised in Faeces
800mg
How much Calcium is metabolised in Kidneys
200mg
How much calcium is found in cells
1.0%
How much calcium in extra cell fluid
0.1%
How much calcium in bone
98.9%
What proportion of Calcium is bound in Plasma
40% Bound to Albumin
What proportion of Calcium is non ionised or complexed to citrate
15%
What proportion of calcium is ionised or free
45%
What is the normal range of plasma calcium
2.20-2.60mmol/l
Increased Albumin does what to Free Calcium
Decreases
Decreased Albumin does what to Free Calcium
Increases
Acidosis does what to Ionised Calcium
Increases thus predisposing to Hypercalcaemia
What responds directly to changes in calcium concentrations
Chief Cells
If Ca2+ Increases what happens to PTH
Decrease
If Ca2+ decreases what happens to PTH
Increase
Alternations in ECF Ca2+ levels are transmitted into Parathyroid cells via?
Calcium Sensoring reCEPTOR
PTH is secreted in response to fall in
Calcium
What mediates conversion of Vit D from inactive to active form
PTH
