Bone marrow is a spongy tissue found in the center of many bones in the human body. The following bones contain either the red or yellow form of bone marrow:
Blood cells are made in the bone marrow. Immature blood cells in the bone marrow, called stem cells, divide and mature to form various types of mature blood cells. These include:
Some diseases such as leukemia result in unhealthy bone marrow. When this happens, the person may need to have a bone marrow transplant. During this procedure, a doctor will take healthy stem cells from one person - the donor - and inject them through a needle into the blood of a person who needs the transplant. The stem cells travel through the blood into the person's bone marrow. Ideally, the stem cells attach and make new blood cells, thus fixing the problem.
Conditions that depress the bone marrow and may require a bone marrow transplant include the following:
Usually, bone marrow comes from a donor. The procedure is much more likely to succeed when the donor's bone marrow closely matches that of the person it is going to. Close relatives such as a sibling or parent are most likely to have matching bone marrow. In some cases, the person may donate his or her own marrow before treatment with chemotherapy or radiation therapy. Then the doctor transplants the person's own bone marrow back into him or her when it is needed.
Donating bone marrow is generally a painless procedure. A doctor will take the bone marrow from the hipbone with a special needle. Most donors are able to go home the same or the next day.
Receiving bone marrow can be more uncomfortable. A doctor will inject or transfuse bone marrow into the person through an intravenous tube, called an IV. An IV is a tube inserted through the skin and into a vein, usually in the chest or neck.