What is the main function of red blood cells?

The primary role of red blood cells, or erythrocytes, is to transport oxygen from the lungs to the tissues throughout the body. They are uniquely designed for this function; red blood cells contain hemoglobin, a protein that binds to oxygen molecules. When blood passes through the lungs, oxygen molecules attach to the hemoglobin, allowing the red blood cells to carry oxygen efficiently through the bloodstream.

While red blood cells can also contribute to the transport of carbon dioxide back to the lungs for exhalation, their main and crucial function is the delivery of oxygen, which is vital for cellular metabolism and energy production. This focus on oxygen transport is essential for survival, as tissues and organs require a constant supply of oxygen to function properly.