Red blood cells

Definition

Red blood cells (RBCs), also known as erythrocytes, are the most common type of blood cell and are responsible for transporting oxygen from the lungs to tissues and carbon dioxide from tissues to the lungs. They lack a nucleus and organelles, allowing more room for hemoglobin, the protein that binds oxygen.

5 Must Know Facts For Your Next Test

1. Red blood cells originate from hematopoietic stem cells in the bone marrow through a process called erythropoiesis.
2. The lifespan of an RBC is approximately 120 days, after which they are typically broken down in the spleen.
3. RBCs have a biconcave shape which increases their surface area for gas exchange and allows them to deform as they navigate through capillaries.
4. Infections like malaria can directly attack RBCs, leading to their destruction and causing symptoms like anemia.
5. Red blood cells express antigens on their surface that determine blood types (A, B, AB, O) which are crucial for blood transfusions.

Review Questions

• What is the primary function of red blood cells?
• Describe the shape of red blood cells and explain its significance.
• How do infections such as malaria affect red blood cells?

Related terms

Hemoglobin:

A protein in red blood cells that binds oxygen and carbon dioxide.

Erythropoiesis: The process by which red blood cells are produced in the bone marrow.

Antigen-Presenting Cells (APCs):

Immune cells that process and present antigens to T-cells to initiate an immune response.