Endocrinology/CaHomeostasis/BloodCaandCT
| Hypocalcemia inhibits CT synthesis, release and blood concentration. Conversely hypercalcemia stimulates CT synthesis, release and blood concentration. CT does not control blood calcium levels however, this is under the control of PTH |
The effect of blood calcium levels on calcitonin secretion
During hypocalcemia you are observing the same response as what you would see with excessive CT release. The rules of negative feedback tell us therefore that hypocalcemia will lead to an inhibition of CT formation and secretion, decreasing CT blood levels which in turn will elevate Ca2+ levels.
During hypercalcemia you are observing the opposite response to what you would see with excessive release of CT. The rules of negative feedback tell us therefore that hypercalcemia will lead to a stimulation of CT formation and secretion, increasing CT blood levels which in turn will decrease Ca2+ levels.
CT levels in the blood are controlled by blood Ca2+ levels in the following manner.
Although CT will modify blood calcium levels as described above the actual blood calcium levels are under the direct control of PTH. PTH will override any response of blood calcium levels to CT.
Challenge Quiz
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<GIFT> //LEVEL:2 //RAND With respect to the negative feedback control, the secretion of calcitonin is adjusted by: {=It’s physiological effect ~It’s blood concentration}
//LEVEL:2 //RAND Hypercalcemia indicates a(n) {=Elevated~Depressed} blood calcium concentration. This is the {=Same~Opposite} as/of the response to calcitonin. The response of the thyroid gland to hypercalcemia is to {Increase~=Decrease} calcitonin synthesis and release.
//LEVEL:2
//RAND
Hypocalcemia indicates a(n) {Elevated~=Depressed} blood calcium concentration. This is the {Same~=Opposite} as/of the response to calcitonin. The response of the thyroid gland to hypercalcemia is to {=Increase~Decrease} calcitonin synthesis and release.
//LEVEL:2 //RAND A decrease in blood levels of calcitonin will cause blood calcium levels to {Increase~Decrease~=Can't be certain}
//LEVEL:2 //RAND An increase in blood levels of calcitonin will cause blood calcium levels to {Increase~Decrease~=Can't be certain}