What does low calcium evoke a response from?

Low calcium levels in the blood, known as hypocalcemia, evoke a response from the parathyroid glands, which secrete parathyroid hormone (PTH). PTH increases calcium levels by promoting the release of calcium from bones, enhancing calcium reabsorption in the kidneys, and stimulating the conversion of vitamin D to its active form, which increases intestinal calcium absorption. This regulatory mechanism helps maintain calcium homeostasis in the body.