Red blood cells, also known as erythrocytes, play a crucial role in transporting oxygen from the lungs to the tissues throughout the body.

RBCs are the most abundant type of blood cell and serve as the primary vehicle for delivering oxygen via the circulatory system. These cells are produced in the bone marrow and subsequently released into the bloodstream. Each red blood cell is packed with a protein called hemoglobin. Hemoglobin is a complex protein that contains iron atoms, which bind with oxygen in the lungs and facilitate its transport to cells across the body.

After delivering oxygen, hemoglobin picks up carbon dioxide, a waste product generated by cellular metabolism, and transports it back to the lungs. In the lungs, carbon dioxide is exchanged for fresh oxygen, allowing the cycle to repeat. This continuous process is known as respiration.

RBCs have a distinctive biconcave shape, resembling a doughnut without a hole. This unique morphology enables them to navigate through the narrowest blood vessels, ensuring that oxygen reaches every cell in the body. Additionally, their shape provides a large surface area, enhancing the efficiency of oxygen and carbon dioxide exchange.

Beyond their respiratory functions, red blood cells also contribute to the body’s immune response. When foreign substances invade the body, RBCs can bind to these substances, assisting in their transport for elimination.

In summary, the primary function of red blood cells is to transport oxygen from the lungs to the tissues while returning carbon dioxide back to the lungs. They also play a supportive role in the immune response of the body.