ANATOMY

Detailed explanation-1: -Sometimes, your parathyroid gland can release too little PTH, which results in low amounts of calcium in your blood (hypocalcemia), or too much PTH, resulting in high amounts of calcium in your blood (hypercalcemia). Both of these conditions can lead to serious health problems.

Detailed explanation-2: -Low levels of PTH stimulate osteoblasts and bone formation whereas prolonged high levels of PTH increase osteoclast activity, causing an increase in bone resorption.

Detailed explanation-3: -Answer and Explanation: c. Parathyroid hormone is responsible for increasing osteoclast activity to release more calcium into the bloodstream. The parathyroid hormone is released in the presence of a lower level of calcium in the bloodstream.

Detailed explanation-4: -When blood calcium levels are low, the osteoclast activity increases. The osteoclasts are bone cells that are responsible for the resorption, or breakdown of bone. When the blood calcium levels are low, the osteoclasts breakdown bone tissues, and the calcium ions are released from bone into the blood.

Detailed explanation-5: -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.