Calcium Control

Question 1

40% of plasma calcium is bound to ?, and thus ?.
Many labs will thus adjust for a low/ high serum albumin to give a measure
of the ? calcium present.
–o If someone has ? albumin, non-adjusted calcium will appear low.
? states increase ionized calcium by ? albumin binding.
? states decrease ionized calcium by ? albumin binding

Answer 1

albumin
inactive
ionized
low
acidotic
decreasing
alkalotic
increasing

Question 2

There are ? parathyroid glands, lying just ? to the thyroid.
The ? cells are responsible for secreting parathyroid hormone (PTH).
o PTH is secreted when plasma calcium levels are ?
o PTH can also be secreted in response to low ? ?, or high ? levels.

Answer 2

4
posterior
chief
low
vit d
phosphate

Question 3

PTH works to ? plasma calcium levels by;
o Directly stimulating calcium ? from ?.
o Directly increasing ? ? calcium ?.
o Indirectly stimulating increased ? calcium absorption.
---• By increasing vitamin D ? in the ?

PTH has a secondary effect of increasing renal ? ?.

Answer 3

increase
reabsorption
bone
renal tubular
reabsorption
GI
activation
kidney
phosphate excretion

Question 4

Vitamin D acts to sustain plasma ? and ? levels by increasing their inflow from the ? ?

–It is also required for normal ? formation.
–Common in ? , liver and ? products.
–Causes of Vitamin D deficiency most
commonly occur in people with inadequate ? exposure, ? conditions, and ? / ? disease.

Answer 4

calcium
phosphate
GIT
bone
fish
dairy
sunlight
malabsorptive
liver/kidney

Question 5

? is secreted by parafollicular / ‘C’ cells of the thyroid gland in response to ? plasma calcium levels.
It acts to ? plasma calcium levels, by antagonism of the effect of ? on the ?.

Answer 5

calcitonin
increased
decrease
PTH
bone

Question 6

The importance of calcitonin in humans is controversial.
o Removal of the ?, and complete calcitonin deficiency does not lead to overt hypercalcaemia.
o Extreme hypersecretion of calcitonin by ? rarely produces hypocalcaemia.
o It is likely that ?/ ? ? levels are adjusted in response to calcitonin changes.

Answer 6

thyroid
tumours
pth
vit d

Question 7

Intestinal uptake of calcium thus depends on the amount of ? calcium in the
lumen, and the presence of ? vitamin D.
90% of renal ? of calcium is related to ? reabsorption in the proximal tubule, with 10% regulated by ? in the distal tubule.

Answer 7

ionized
activated
excretion
sodium
pth