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When is erythropoietin released by the kidneys?


Option: 1

When oxygen levels are high

Option: 2

When the rate of ultrafiltration falls

Option: 3

When blood pressure is elevated


Option: 4

When calcium levels are low

Answers (1)


Erythropoietin is a hormone that is primarily produced and released by the kidneys, specifically by specialized cells in the kidney called the interstitial cells of the renal cortex. Its primary function is to stimulate the production of red blood cells (RBCs) in the bone marrow.

Erythropoietin release is regulated by the oxygen levels in the body. When the oxygen levels in the tissues are low, such as during conditions of decreased oxygen supply or increased oxygen demand, the kidneys sense this oxygen deficiency. In response, the interstitial cells of the renal cortex release erythropoietin into the bloodstream.

The release of erythropoietin is triggered specifically when the rate of ultrafiltration, which is the initial step of urine formation in the kidneys, falls. The interstitial cells sense this decrease in the rate of ultrafiltration as a signal that oxygen supply to the tissues may be compromised. As a result, erythropoietin is released to stimulate the bone marrow to produce more red blood cells.

By increasing the production of red blood cells, erythropoietin helps to enhance the oxygen-carrying capacity of the blood, ensuring that the body's tissues receive an adequate supply of oxygen.

Therefore, erythropoietin is released by the kidneys when the rate of ultrafiltration falls, indicating a potential decrease in oxygen supply to the tissues.

Option 2 is the correct answer.

Posted by

Anam Khan

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