Anatomy Practice Exam

The destruction of old blood cells, primarily red blood cells, by the spleen results in the recycling of their components, making option D the correct choice. When red blood cells become senescent or damaged, they are phagocytized by the macrophages in the spleen. During this process, hemoglobin is broken down into heme and globin.

The globin portion is further degraded into amino acids, which can be reused to synthesize new proteins. The heme is broken down into iron and bilirubin. The iron is then stored in the liver or recycled back into the bone marrow for the production of new hemoglobin, while bilirubin is processed by the liver and eventually excreted as bile.

This recycling process is vital because it allows the body to reuse essential components from old blood cells rather than expelling them outright or storing them unutilized. Thus, the functioning of the spleen not only helps to maintain a healthy population of blood cells but also conserves important bodily resources.