Bone Marrow FAQs
Q. What is Bone marrow?
Ans. Bone marrow is a soft, spongy substance (tissue) found inside flat and long bones of the body. The marrow fills the empty spaces in the bones.
Q. How many types of bone marrow are there?
Ans. Bone marrow has two categories as below:
1) Red Marrow or hematopoietic (also known as myeloid tissue) majorly contains red blood cells, platelets and white blood cells. As per the body mechanism, most of the bone marrow is red as lots of new blood cells required for the growing body in younger age. Red bone marrow helps the body in its everyday functions.
Red marrow is found mainly in the flat bones, such as the hip bone, sternum (breast) bone, skull, ribs, vertebrae, and shoulder blades, as well as in the metaphyseal and epiphyseal ends of the long bones, such as the femur, tibia, and humerus, where the bone is spongy.
2) Yellow Marrow or stromal is found in medullary cavity of adults. Some white blood cells develop in yellow marrow also. As a person gets older, about half of the red bone marrow is slowly replaced by yellow bone marrow.
Yellow marrow is made mostly of fat and is found in the hollow centres of long bones, such as the thigh bones. It does not make blood cells or platelets. The colour of yellow marrow is due to large number of the fat cells. It helps the body to survive extreme cases of hunger and blood loss.
Both yellow and red bone marrow has many small and large blood vessels and veins running through them to let nutrients and waste in and out of the bone.
Q. How are blood cells made in the bone marrow?
Ans. Bone marrow produces stem cells and other substances, which in turn make blood cells. These blood cells are called red blood cells, white blood cells and platelets. Blood cells start off as young, immature stem cells but once developed, these cells do not live for a long time inside the body.
Q. Is bone marrow a tissue or an organ?
Ans. The red bone marrow is a key element of the lymphatic system, being one of the primary lymphoid organs that generate lymphocytes from immature hematopoietic progenitor cells. The bone marrow and thymus constitute the primary lymphoid tissues involved in the production and early selection of lymphocytes.
Q. What does it mean to have low bone marrow?
Ans. When bone marrow in a person’s body does not make sufficient type/s (one or more) of blood cells, bone marrow and blood count goes down to below average level. This condition is called a low bone marrow or blood count cytopenia.
Q. Why are blood cells so important?
Ans. All three types of cells which include red, white and platelets cells present in the body are vital to be alive.
- Red blood cells are in-charge of carrying much-needed oxygen throughout the body.
- White blood cells make up the immune system, fighting off illnesses and helping the body to heal.
- Platelets help making blood clot therefore stop bleeding.
Q. What are the different types of white blood cell?
Ans. There are three very important types of white blood cells, essential to the proper functioning of the body's immune system, which fights infection.
(a) Neutrophils and (b) Macrophages — fight bacterial and fungal infections by ‘eating’ germs
(c) Lymphocytes — fight bacterial, viral and fungal infections. T lymphocytes, also called T cells, attack viruses and other germs. T cells from the donor also can attack the recipient resulting in a reaction called graft versus host disease. T cells from the recipient can reject the donor bone marrow cell resulting in graft failure. B lymphocytes make antibodies which help destroy germs in our body.