Red blood cells flowing

Red blood cells are anucleated cells that carry oxygen throughout the human body, essential for cellular metabolism.

About this subject

Red blood cells, also known as erythrocytes, are the most abundant cells in human blood. Produced in the bone marrow from stem cells, they lose their nucleus during maturation, resulting in a biconcave disc shape. This shape increases the surface area for gas exchange and allows them to deform to pass through narrow capillaries.

The primary function of red blood cells is to transport oxygen from the lungs to tissues and to remove carbon dioxide. This is made possible by hemoglobin, an iron-rich protein that reversibly binds oxygen. Each red blood cell contains about 270 million hemoglobin molecules, enabling it to carry up to 1 billion oxygen molecules per cycle.

Erythrocytes have an average lifespan of approximately 120 days. After that, they are removed by the spleen and liver. Normal counts range from 4.5 to 6 million per microliter of blood in adults. Low levels may indicate anemia, while high levels can be associated with polycythemia. Additionally, malaria is a parasitic disease that specifically infects red blood cells, causing their destruction.

Historically, red blood cells were discovered by Antonie van Leeuwenhoek in the 17th century. Subsequent studies identified blood groups and Rh factors, essential for safe transfusions. Knowledge about erythrocytes is also crucial for understanding disorders such as sickle cell anemia, where abnormal cell shape impairs blood flow.

Frequently Asked Questions

What is the main function of red blood cells?

To carry oxygen from the lungs to body tissues and assist in removing carbon dioxide.

Why do red blood cells lack a nucleus?

Losing the nucleus during maturation provides more space for hemoglobin and allows the cell to become flexible for navigating capillaries.

What happens when red blood cell count is low?

It may cause anemia, with symptoms such as fatigue, pallor, and shortness of breath, due to reduced oxygen transport.