Question

Erythropoietin is hormone produced from
a. Thymus
b. Pituitary
c. Heart
d. Kidney

Answer 1

Erythropoietin, also known as EPO, is a hormone that stimulates the production and maintenance of red blood cells (erythropoiesis) by the bone marrow. It is the key regulator of red cell production.

Complete answer:
Hormones are chemical messengers or information molecules formed by the cells of an endocrine gland. Hormones are carried to the target cells through the circulatory system. Hormones are required in specific quantities.

Endocrine system is a system of endocrine glands and hormones producing tissues or cells that are located in different parts of the body. The major glands that make up the endocrine system are:- pituitary gland, pineal body, thyroid gland, parathyroid gland, adrenal gland, pancreas and thymus gland. In addition to these major glands, some other organs such as the kidney, testes (in males), ovaries (in females), gastrointestinal tract, liver and heart also produce hormones.

Kidneys are mainly excretory organs that ensure that unwanted substances (waste products) and excess water are removed from the bloodstream. The justa-glomerular cells of kidney produce two hormones:-
- Erythropoietin (EPO)
- Renin

- The erythropoietin hormone produced from the kidney stimulates the formation of red blood cells (RBCs) in bone marrow. It is also called hematopoietin or hemopoietin.
- Rennin changes the angiotensinogen of the liver into angiotensin. It also stimulates the rate of ultra filtration.

Option A: Thymus gland is present in the upper part of the chest covering the lower end of the trachea, just in front of the heart. It is bilobed, pyramid shaped and pink in colour. Thymus gland secretes thymosin hormones. It plays an important role in development of the immune system. Thymus is a temporary gland that is generated in old individuals.

Option B: Pituitary gland is a pea-shaped endocrine gland, also known as master endocrine gland. It lies in a cavity called the sella turcica of the sphenoid bone of the skull. Anterior lobe of pituitary gland produces:- growth hormones (GH), thyroid stimulating hormones (TSH), adrenocorticotropic hormone (ACTH), luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin (PRL). Intermediate lobe of pituitary gland produces:- melanocyte stimulating hormone (MSH). Posterior lobe pituitary gland produces:- oxytocin (OT) and vasopressin .

Hence, the correct answer is option (D).

Note: Erythropoietin is a hormone produced by justa-glomerular cells of the kidney. The specialised cells in the kidney are capable of detecting and responding to low levels of oxygen through increased production of erythropoietin. When the levels of oxygen in the blood circulation are appropriate, the production of erythropoietin is reduced. But, when the oxygen levels go down, the production of erythropoietin goes up. It facilitates the production of more red blood cells to transport more oxygen throughout the body and thus increases the oxygen levels in the tissue.