What is the primary function of red blood cells?

The primary function of red blood cells is to transport oxygen throughout the body. These cells contain hemoglobin, a protein that binds oxygen in the lungs and carries it to various tissues and organs. The efficient delivery of oxygen is crucial for cellular metabolism and overall bodily function, as oxygen is necessary for the production of energy in cells.

In addition to oxygen transport, red blood cells also play a minor role in transporting carbon dioxide, a waste product of metabolism, from tissues back to the lungs for exhalation. This dual role in gas exchange is vital for maintaining proper physiological function.

Red blood cells do not directly fight infections, regulate blood pH levels, or produce hormones, as these functions are primarily associated with other components of the blood and the body's systems. For example, white blood cells are responsible for combating infections, while the kidneys and respiratory system are involved in pH regulation. Hormone production is primarily a function of endocrine glands. Thus, the transport of oxygen is the definitive and most critical role of red blood cells.