Red Blood Cell (Erythrocyte)

The **erythrocyte**, or **red blood cell** (RBC), is the most abundant type of cell in blood: A single drop of blood contains millions of erythrocytes but only thousands of leukocytes. On average, males have about 5.4 million erythrocytes per microliter (µL) of blood, while females have approximately 4.8 million per µL. Erythrocytes are estimated to comprise roughly 25 percent of all cells in the body. Their primary functions are to transport inhaled oxygen from the lungs to body tissues and to carry about 24 percent of carbon dioxide waste from tissues back to the lungs for exhalation. Unlike leukocytes, which typically exit blood vessels to carry out immune functions, erythrocytes remain within the vascular system; any movement of erythrocytes out of blood vessels is considered abnormal. *LICENSES AND ATTRIBUTIONS CC licensed content, Shared previously, Erythrocytes, Authored by: OpenStax College. License: CC BY: Attribution. License Terms: Download for free at https://cnx.org/contents/9SrcxH7k@4/Erythrocytes* ## Keywords red blood cell hemoglobin oxygen bone marrow