Red blood cells

Red blood cells, also known as erythrocytes, are the most common type of blood cell and the principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system. They take up oxygen in the lungs, and release it while squeezing through the body's capillary network.

Structure

Red blood cells are biconcave discs, denucleated cells (lacking a cell nucleus) which allows for more room to carry hemoglobin, their primary function being to transport oxygen. They are flexible and can change shape when necessary.

Function

The primary function of red blood cells is to transport oxygen from the lungs to the tissues of the body. Hemoglobin, an iron-containing protein in red blood cells, serves to bind with oxygen in the lungs and carry it to the tissues where it is released.

Production

Red blood cells are produced in the bone marrow and are released into the bloodstream when they are mature. The production of red blood cells is regulated by the hormone erythropoietin, which is produced by the kidneys.

Lifespan

The lifespan of a red blood cell is approximately 120 days. After this time, they are removed from the bloodstream by the spleen.

Disorders

There are several disorders that can affect the red blood cells, including anemia, in which there is a deficiency of red blood cells; polycythemia, an excess of red blood cells; and sickle cell disease, a condition in which red blood cells are abnormally shaped.

See also

• Hematology
• Hemoglobin
• Blood transfusion

Red blood cells Resources
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