Super Easy Short Calcium presentatin [Due in 2hours]

Calcitonin- if blood/serum calcium levels are higher than usual, calcitonin hormone is released from the thyroid gland to lower levels back to normal. This is done through various pathways including hindering bone resorption and kidney tubular reabsorption thus excreting calcium in urine.

Parathyroid- the parathyroid gland has calcium level sensing receptors which secrete parathyroid hormone when levels are too high / too low and need to get back within normal range. Like calcitonin, this is accomplished through various pathways including stimulating bone resorption to increase extracellular calcium levels. Also, it indirectly increases levels by stimulating calcitriol production which leads to enhanced calcium absorption from the intestine. Finally, it suppresses calcium loss in urine by stimulating kidney tubular reabsorption. Conversely, it decreases calcium levels if its receptors sense too high calcium levels. This is done by a feedback mechanism which turns the receptors off thus stopping the secretion of parathyroid hormone. Moreover, calcitriol receptors work in a feedback manner to suppress parathyroid hormone production.

Calcitriol (Vitamin D3) - increases calcium levels by encouraging the expression of several proteins whose function involves transporting calcium from the intestinal lumen into the blood. Also, it acts on bone to increase calcium levels by inducing the expression of osteocalcin. Finally, it acts on the kidney to increase calcium levels by stimulating tubular reabsorption. As stated in the previous paragraph, it works in a feedback way to decrease calcium levels if too high.

PTG- parathyroid gland

PTH- parathyroid hormone

“C” cells- parafollicular cells in thyroid gland

CT- calcitonin