what part of the body makes platelets site:webmd.com
Bone marrow. This is soft tissue found mainly inside the long bones of the arms and legs, the vertebrae, and the pelvic bones of the body. It is made up of red marrow, which produces red and white blood cells and platelets, and yellow marrow, which contains fat and connective tissue and produces some white blood cells. The spleen, which filters the blood by removing old or damaged blood cells and platelets and helps the immune system by destroying bacteria and other foreign substances. White blood cells. These blood cells are made in the bone marrow and protect the body against infection.