Changes

===Calcitonin===

===Calcitonin===

Calcitonin acts to decrease calcium levels in the plasma. It has an overall weaker effect than PTH.

Calcitonin acts to decrease calcium levels in the plasma. It is overall a weaker regulatory mechanism than PTH.

Secreted by the parafollicular cells of the Thyroid gland, Calcitonin is stimulated by hypercalcemia, and has the opposite effects of PTH on the bone:

Secreted by the parafollicular cells of the Thyroid gland, calcitonin is stimulated by hypercalcemia, and has the opposite effects of PTH on the bone:

*Fast Phase - puts calcium into bone fluid by inhibiting osteoclasts' absorptive abilities

*Fast Phase - puts calcium into bone fluid by inhibiting osteoclasts' absorptive abilities

*Slow Phase - puts calcium into bone by reducing formation of new osteoclasts.

*Slow Phase - puts calcium into bone by reducing formation of new osteoclasts.