Erythrocytes

Erythrocytes (also known as red blood cells) are the most common type of blood cell and the principal means of delivering oxygen (O2) to the body tissues via the blood flow through the circulatory system. They take up oxygen in the lungs or gills and release it while squeezing through the body's capillaries.

Structure and Function

Erythrocytes are biconcave in shape, which increases the cell's surface area and facilitates the diffusion of oxygen and carbon dioxide. This shape is maintained by a cytoskeleton made up of several proteins. Erythrocytes contain a protein called hemoglobin, which can bind to oxygen and is responsible for the red color of the cells.

Production and Lifespan

Erythrocytes are continuously produced in the red bone marrow of large bones, in a process called erythropoiesis. The production is regulated by the hormone erythropoietin, which is released by the kidneys in response to low oxygen levels. Once mature, erythrocytes circulate in the body for about 120 days. After this, they are broken down in the spleen and the components are recycled.

Clinical Significance

Abnormalities in the number or function of erythrocytes can lead to several diseases. Anemia is a condition characterized by a decrease in the number of erythrocytes or a decrease in the amount of hemoglobin they contain, which results in decreased oxygen-carrying capacity. Polycythemia is a condition characterized by an increase in the number of erythrocytes, which can increase the viscosity of the blood and make it harder for the heart to pump.

See Also

• Anemia
• Polycythemia
• Hemoglobin
• Erythropoiesis
• Erythropoietin

References

Erythrocytes Resources
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