Question

Which of the following is true of parathormone (PTH)?

Multiple Choice

1-Parathormone is secreted by the pituitary gland.



2-Parathormone is secreted in response to high levels of plasma calcium (hypercalcemia).

3-Parathormone decreases the intestinal absorption and renal reabsorption of calcium ions.

4-Parathormone is secreted in response to low levels of plasma calcium (hypocalcemia).

Answer 1

Parathormone (PTH) is a hormone secreted by the parathyroid glands in response to low blood calcium levels. It stimulates the release of calcium from bones, increases calcium reabsorption in the kidneys, and promotes the absorption of dietary calcium in the intestines.

Step-by-step explanation:

Parathormone (PTH) is a hormone produced by the parathyroid glands in response to low blood calcium levels. PTH has several functions in the body:

1. Stimulating the release of calcium from bones by activating osteoclasts.
2. Inhibiting osteoblasts, which are involved in the formation of new bone.
3. Increasing the reabsorption of calcium in the kidneys, reducing the loss of calcium in urine.
4. Stimulating the production of calcitriol, the active form of vitamin D, in the kidneys.
5. Promoting the absorption of dietary calcium in the intestines.

Therefore, the correct statement about PTH is option 4: Parathormone is secreted in response to low levels of plasma calcium (hypocalcemia).