Final answer:
The spleen is primarily responsible for removing old and damaged red blood cells from the body, with macrophages within the spleen performing phagocytosis. The liver and bone marrow also contribute to this process.
Step-by-step explanation:
The structure in the body that removes old red blood cells is called the spleen. Within the spleen, old and damaged erythrocytes (red blood cells) are phagocytized by macrophages, which are a type of myeloid phagocytic cell. Additionally, the liver also plays a role in this process by filtering the blood and removing damaged or defective red blood cells.
Red blood cells have a lifespan of about 120 days, after which they become worn out and need to be removed from the circulation. This process of phagocytosis also occurs in the liver and bone marrow to a lesser extent. The components of degraded erythrocytes' hemoglobin are then further processed and recycled.
Red blood cells are produced in the bone marrow and are responsible for delivering oxygen to the body's cells and removing carbon dioxide. Mature red blood cells lack a nucleus or mitochondria, which allows for more hemoglobin to be present and thus increases their oxygen-carrying capacity.