Some of the bones in our body such hip and thigh bones, contain a spongy tissue substance inside them. This substance is known as bone marrow. Filled in the medullary cavities of the bones, it is soft and gelatinous in nature and contains immature cells or the stem cells. Situated in the large bones, it produces the new blood cells. The 4% of the human body weight is due to presence of Bone marrow and in a healthy adult this nearby 2.6 kg.
In the human body, there are two types of bone marrows:
Red bone marrow (or myeloid tissue): This substance is the main element that produces the red blood cells, white blood cells and platelets.
Yellow bone marrow: This type mainly contains the fat cells.
Both types of bone marrow possess the similar characteristics they are highly vascular and also enriched with many capillaries and blood vessels that altogether make it a rich vascular organ. At the birth time and during the early childhood, the bone marrow is usually red in the color. As the human body grows and ages, it converts in yellow. In an adult human body half of the bone marrow is yellow.
Bone marrow is responsible for the forming and generating the blood cells that are essential for our body in many ways.Red blood cells or erythrocytes transfer oxygen to the tissues. Due to platelets, there is less possibility of bleeding and clotting of the blood. Also the other micro substances produced here help the human body to fight against the infection from bacteria, fungi and other parasites, and kill or isolate invading cells.
Mesenchymal stem cells lie around the central bore of the bone. These cells have a great capacity to create cells for the body such as:
Osteoblasts to form bones
Chondrocytes to form cartilage
Myocytes to form muscles
And many others.
Alongwith the above specific stem cells, there are endothelial stem cells are also present in the bone marrow who are responsible for the formation of blood vessels.
Bone marrow pathology and diagnosis
Bone marrow is subjected to many relative diseases such as leukemia, anemia, pancytopenia, multiple myeloma, MDS (myelodysplastic syndrome) and some others. These can be figured out through a bone marrow biopsy or bone marrow aspiration that is actually an examination of bone marrow tissues and very painful experience. It is also a main study point while cancer chemotherapy.
Today, medical science is capableenough to transplant the bone marrow in a diseased person successfully.