What are Red Blood Cells?

Red blood cells, also known as erythrocytes, are the most common type of blood cell in the human body. They are responsible for transporting oxygen from the lungs to the rest of the body, and for carrying carbon dioxide, a waste product, back to the lungs to be exhaled.

Structure of Red Blood Cells

Red blood cells are disk-shaped and have a dimple in the center, giving them a biconcave shape. This shape provides a large surface area for the exchange of oxygen and carbon dioxide. Red blood cells do not have a nucleus, which allows for more space to carry oxygen and carbon dioxide.

Function of Red Blood Cells

The primary function of red blood cells is to transport oxygen from the lungs to the body tissues and organs, and to carry carbon dioxide from the body tissues and organs back to the lungs for exhalation. Red blood cells contain hemoglobin, a protein that binds to oxygen in the lungs and releases it in the tissues, and binds to carbon dioxide in the tissues and releases it in the lungs.

Life Cycle of Red Blood Cells

The average lifespan of a red blood cell is about 120 days. They are produced in the bone marrow and eventually broken down and recycled by the spleen and liver.

Study Guide

1. What is the primary function of red blood cells?
2. Describe the structure of red blood cells.
3. Where are red blood cells produced?
4. What is the role of hemoglobin in red blood cells?
5. How long is the average lifespan of a red blood cell?