CAMRT Radiography Practice Exam

Which anatomical structure is primarily responsible for the production of blood cells?

1. Liver

2. Spleen

3. Bone marrow

4. Kidneys

The correct answer is: Bone marrow

The primary anatomical structure responsible for the production of blood cells is bone marrow. Bone marrow is a vital part of the hematopoietic system, which is where hematopoiesis, or the formation of blood cells, occurs. This includes the production of red blood cells, white blood cells, and platelets, all crucial for maintaining healthy blood and supporting various bodily functions. Bone marrow exists in two types: red marrow, which is active in blood cell production, and yellow marrow, which primarily serves as a fat storage reserve. In adults, red marrow is predominantly found in flat bones such as the skull, ribs, and pelvis, as well as in the ends of long bones. While the liver, spleen, and kidneys have roles in blood-related functions—such as filtering blood, producing certain blood proteins, and regulating blood pressure—they do not actively produce blood cells in the same way bone marrow does. The liver is involved in synthesizing clotting factors and proteins in the blood, the spleen plays a role in the recycling of iron and managing blood cells, and the kidneys help regulate blood composition and produce erythropoietin, a hormone that stimulates red blood cell production in the bone marrow. These functions support blood health but do