GENERAL HISTOLOGY

Detailed explanation-1: -Parathyroid hormone is directly involved in the bones, kidneys, and small intestine. In the bones, PTH stimulates the release of calcium in an indirect process through osteoclasts which ultimately leads to the resorption of the bones.

Detailed explanation-2: -PTH actions on osteoblasts An increase in osteoblast differentiation rather than osteoblast proliferation appears to be the main mechanism by which PTH stimulates osteoblastogenesis. Indeed, PTH arrests the cell cycle progression of osteoblasts, increasing their commitment to a differentiated osteogenic fate [69].

Detailed explanation-3: -Calcitonin inhibits (blocks) the activity of osteoclasts, which are cells that break down bone. When osteoclasts break down your bone, the calcium from your bone is released into your bloodstream. Therefore, the temporary blocking of osteoclasts by calcitonin reduces the amount of calcium that enters your blood.