Question

Hormone calcitonin is secreted by
A. Thyroid
B. Pancreas
C. Parathyroid
D. Adrenal medulla
E. Anterior Pituitary

Answer 1

Hint:All the endocrine glands are under the control of the pituitary gland. The pituitary gland releases certain hormones that regulate the activity of other endocrine glands. The action of hormones released by pituitary glands stimulates other glands to release their respective hormones.

Complete answer:
The pituitary gland releases TSH i.e. Thyroid-stimulating hormone. This hormone acts on thyroid follicles in the thyroid gland, and two hormones are synthesized. These hormones are tetraiodothyronine or thyroxine also known as T4 and Triiodothyronine (T3). These are iodine hormones. Out of these two hormones, T3 is more potent and more active than T4.
Along with these hormones, parafollicular cells of the thyroid gland secrete and release hormone calcitonin, this hormone decreases the calcium levels in the blood by increasing calcium absorption by bones.
The pancreas is a dual gland i.e it performs the function of both exocrine as well as and endocrine glands. This endocrine part has a variety of cells present like alpha, beta, gamma, delta cells; and each cell synthesizes and releases hormones. For example, alpha cells synthesize and release hormone glucagon, which increases the blood glucose levels whereas blood glucose levels are decreased by the hormone insulin. Insulin is secreted by beta cells. Delta cells of the pancreas release the hormone somatotropin.
The hormones released by the parathyroid gland are called parathyroid hormones, Collip’s hormone, or parathormone (PTH). This hormone helps in maintaining blood calcium levels along with calcitonin. PTH is also called a hypercalcemic hormone that helps to increase blood calcium levels.
As the adrenal gland is divided into two parts, the outer part is called the adrenal cortex while the inner part is called the adrenal medulla. The adrenal gland gets activated under the influence of the hormone ACTH i.e. Adrenocorticotropic hormone.
Hence, the correct answer to the given question is option A. Thyroid

Note: An increase of hormones from thyroid glands results in a medical condition called hyperthyroidism and when thyroxine levels in blood decrease this condition is called hypothyroidism.