As explained by About.com, red bone marrow’s primary job is to produce blood cells. Red bone marrow produces two types of stem cells. Myeloid stem cells develop into red blood cells, platelets or myeloblast cells, which in turn develop into a type of white blood cell called a granulocyte. Lymphoid stem cells turn into lymphoblast cells, which eventually develop into another type of white blood cell called a lymphocyte.
While red marrow also removes damaged red blood cells from the blood, this job is also carried out by the spleen and liver. About.com states that the red marrow contains an abundance of blood vessels, which keeps the tissue well nourished. Yellow marrow, which primarily resides in spongy bones and the shafts of the limb bones, serves as a storage site for fat. If a person suffers from extreme blood loss, the body can convert yellow marrow to red marrow. The new red marrow can then produce replacement blood cells.
Red bone marrow is part of the body’s lymphatic system, according to About.com. Red bone marrow is primarily found in the pelvis, spine, skull, sternum and shoulder blades. Additionally, the long bones of the arms and legs contain some red marrow near where they attach to the pelvis or shoulder.