Ncert Exercises & Solutions

37. Calcium plays a very important role in the formation of bones. Write on the role of endocrine glands and hormones responsible for maintaining calcium homeostasis.

The endocrine glands and hormones that are responsible for maintaining calcium homeostasis, are thyroid and parathyroid glands and their associated hormones are calcitonin and Parathyroid Hormone (PTH).

(i) Parathyroid glands are the glands developed from the endoderm of the embryo. The cells of parathyroid glands are of two types, i.e., chief cells and oxyphil cells. The chief cells of the parathyroid glands secrete parathyroid hormone (PTH).

This hormone (PTH) is involved in regulating calcium and phosphate balance between the blood and other tissue. It mobilises the release of calcium into the blood from bones. PTH increases calcium reabsorption by the body organs like intestine and kidneys.

(ii) Thyroid gland is the largest endocrine gland located anterior to the thyroid cartilage of the larynx in the neck. This gland plays a vital role in maintaining calcium homeostasis. It releases thyrocalcitonin hormone produced by the parafollicular cells, also called 'C' cells.

This hormone is secreted when the calcium level in blood gets high. It is a 32 amino acid peptide hormone that lowers the calcium level by suppressing release of calcium ions from the bones. Thus, calcitonin has an action opposite to that of the parathyroid hormone on calcium homeostasis.

NEET Information

courses

Company

Botany Questions

Chemistry Questions

Physics Questions

Zoology Questions