By stimulating which type of cells does calcitonin increase calcium and phosphate ion concentrations?

Calcitonin is a hormone produced by the parafollicular cells (also known as C cells) of the thyroid gland that plays a crucial role in regulating calcium and phosphate levels in the body. Its primary function is to reduce the concentration of calcium and phosphate in the blood, particularly by acting on osteoblasts, which are specialized cells involved in bone formation.

When calcitonin is released, it stimulates osteoblasts to increase the deposition of calcium into the bone matrix. This occurs because osteoblasts are responsible for the synthesis and mineralization of bone tissue. By promoting the activity of osteoblasts, calcitonin facilitates the incorporation of calcium and phosphate ions from the bloodstream into the bones, thereby lowering their concentrations in circulation.

In summary, the mechanism by which calcitonin increases calcium and phosphate ion concentrations involves the stimulation of osteoblasts, leading to enhanced deposition of these minerals into the bone, effectively managing their levels in the plasma.