Physiology - An introduction to calcium metabolism Flashcards
what are the 3 main structures involved in calcium balance
bone
kidney
intestine
which of these has a higher conc of calcium normally
a.plasma
b.cell
a.plasma
2.5 mmol /L
what is most of the protein bound calcium bound to
a.haemoglobin
b.albumin
c.globulin
b.albumin
some bound to globulin
half free
what happens to the amount of free calcium as pH decreases
a.increase
b.decrease
a.increase
H+ displaces ca2+ on albumin and so more ca2+ is free and biologically active
which 3 hormones are responsible for regulation of body calcium
parathyroid hormone
vitamin d (calcitrol / 1,25 dihydroxycholecalciferol)
calcitonin
when is parathyroid hormone secretion increased
a.low calcium, high phosphate , low mg
b.high calcium, low phosphate, high mg
c.high calcium, high phosphate, high mg
a.low calcium, high phosphate , low mg
calcium and phosphate inversely proportional
what are the effects of increased pth on bone
a.rapid exchange from ecf to bone pool, bone production by osteoblasts
b.rapid exchange from bone pool to ecf, bone resorption by osteoclasts
b.rapid exchange from bone pool to ecf, bone resorption by osteoclasts
what are the effects of increased pth on bone
a.rapid exchange from ecf to bone pool, bone production by osteoblasts
b.rapid exchange from bone pool to ecf, bone resorption by osteoclasts
b.rapid exchange from bone pool to ecf, bone resorption by osteoclasts
what is the effect of pth on the kidney
a.reabsorption of ca2+, excretion of phosphate, formation of vitamin D
b.excretion of calcium, reabsorption of phosphate
a.reabsorption of ca2+, excretion of phosphate, formation of vitamin D
what is cholecalcefirol from skin converted to in the liver
a.25 hydroxycholecalciferol
b. 1,25 dehydroxycholecalciferol
a.25 hydroxycholecalciferol
what is 25 hydroxycholecalciferol from liver converted to in the kidney when parathyroid hormone is secreted
a.cholecalciferol
b. 1,25 dehydroxycholecalciferol
b. 1,25 dehydroxycholecalciferol
what effect does 1,25 dehydroxycholecalciferol have in the intestine
a.enhances ca 2+ absorption
b.decreases ca 2+ absorption
a.enhances ca 2+ absorption
pth released in low calcium and stimulates the production of 1,25 d. in the kidney
steroid hormone so binds to nuclear receptor and upregulates transcription of calcium transporters so more calcium into cell
hat effect does 1,25 dehydroxycholecalciferol. have in the bone
a.increase calcification and mineralisation
b. decrease calcification and mineralisation
a.increase calcification and mineralisation
for normal osteoblast function
lack of dietary vit D / sunlight , malabsorption of fats and failure to form calcitrol eg chronic renal failure are all causes of what condition]
a.osteopososis
b.osteomalacia
c.osteosarcoma
b.osteomalacia
which cells in the thyroid gland produce calcitonin
a.follicle cells
b.c cells
c.kuppfer cells
d.colloid
b.c cells
