Red Blood Cells

Red Blood Cells (RBCs), also known as erythrocytes, 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

The cytoplasm of erythrocytes is rich in Hemoglobin, an iron-containing biomolecule that can bind oxygen and is responsible for the red color of the cells. The cell membrane is composed of proteins and lipids, and this structure provides properties essential for physiological cell function such as deformability and stability while traversing the circulatory system.

Function

The primary function of red blood cells is to transport oxygen from the lungs to the body tissues, and carbon dioxide as a waste product away from the tissues and back to the lungs. Because mature red blood cells lack a nucleus and most organelles, including Mitochondria, they cannot perform certain cellular functions, like anaerobic respiration. They are also unable to synthesize proteins.

Production

Red blood cells are produced through a process named Erythropoiesis, developing from committed stem cells to mature red blood cells in about 7 days. When matured, in a healthy individual these cells live in blood circulation for about 100 to 120 days (and 80 to 90 days in a full term infant). At the end of their lifespan, they are removed from circulation.

Clinical significance

Abnormalities in red blood cells can be a sign of various medical conditions. A decrease in red blood cells (anemia), an increase (polycythemia), or an abnormality in shape or structure can all indicate disease.

See also

• Hematology
• Hemoglobin
• Erythropoiesis

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