Question

Erythropoietin is produced by
A. Thymus
B. Pituitary
C. Heart
D. Kidney

Answer 1

Hint: Erythropoietin or haematopoietic is a hormone, produced mainly by the specialised cells of the kidneys. It stimulates the production and maintenance of red blood cells. Having more red blood cells raises haemoglobin levels throughout the body.

Complete answer: Erythropoietin (EPO) is a hormone produced chiefly by the kidneys. It plays an important role in the production of red blood cells (RBCs), which carry oxygen from the lungs to the rest of the body. Erythropoietin is manufactured and secreted into the blood by the kidneys in response to hypoxemia (low blood oxygen levels). EPO is carried to the bone marrow, where it stimulates production of red blood cells (RBCs). The hormone works only for a short period of time and then removed from the body in the urine.
The amount of erythropoietin secreted depends upon how low the oxygen level is and the ability of the kidneys to produce erythropoietin. Continuous production and secretion of erythropoietin occurs until oxygen levels in the blood rise to normal or near normal, then its production falls. This dynamic feedback helps maintain sufficient oxygen levels and a relatively stable number of RBCs in the blood.

Among the given options:
Thymus gland secretes a hormone named thymosin which stimulates the development of certain kinds of white blood cells involved in producing immunity. It also speeds up the attainment of sexual maturity.

Pituitary hormones play an essential role in regulating the functions of various other endocrine glands and thus maintaining overall hormone levels in the blood. The major hormones released from anterior pituitary are thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), adrenocorticotropic hormone (ACTH), luteinizing hormones (LH), growth hormone (GH) or somatotropic hormone (STH) and prolactin. Posterior pituitary secretes oxytocin and antidiuretic hormone (ADH).

The heart (cardiac) cells of the body release a peptide hormone which is known as Atrial natriuretic factor (ANF) or atrial natriuretic peptide (ANP). This hormone is a potential vasodilator that helps to regulate the blood volume and arterial blood pressure.

So, the correct answer is option D.

Note: The oxygen shortage in the body stimulates the kidney cells to secrete a hormone called erythropoietin into the blood. It stimulates the bone marrow to increase the production of RBCs.