Red blood cells, also known as erythrocytes, are essential cells in the circulatory system responsible for transporting oxygen from the lungs to the tissues and removing carbon dioxide to be exhaled. These cells contain a protein called hemoglobin, which binds to oxygen in the lungs and releases it to the body’s cells. Hemoglobin is what gives red blood cells their characteristic color.

Red blood cells are produced in the bone marrow and have a lifespan of approximately 120 days. They have a biconcave disc shape, which increases their surface area to facilitate gas exchange. At the end of their life cycle, they are removed from circulation by the spleen and liver. Any alteration in the production or function of red blood cells can lead to conditions such as anemia, where there is a reduction in the blood’s capacity to carry oxygen, resulting in symptoms like fatigue and weakness.