What is the function of red blood cells?

Red blood cells, also known as erythrocytes, have the primary function of transporting oxygen from the lungs to the tissues and organs throughout the body. They contain a protein called hemoglobin, which binds to oxygen molecules in the lungs. Once the red blood cells circulate to the body's tissues, hemoglobin releases the oxygen for use by cells, which is essential for cellular respiration and energy production. Additionally, red blood cells have a biconcave shape that increases their surface area for oxygen absorption and facilitates easier movement through the blood vessels. This unique structure and function make them crucial for maintaining the body's oxygen levels and overall metabolic processes.