What is Bone Marrow?

What is Bone Marrow?

Bone marrow is a spongy tissue that fills with blood cells. It’s located inside the hollow middle of long bones, such as the femur bone in your leg or humerus bone in your upper arm.

They work together to form red blood cells that carry oxygen throughout your body—white blood cells that fight infection and help you recover from illness. And platelets, which help stop bleeding by clotting blood vessels. Bone marrow also helps store energy in the form of fat cells.

As per scientists’ latest research and study, marrow in their wrists produces new fat cells in women. The marrow in both sexes is responsible for keeping us alive and healthy. Researchers have claimed that about 25 percent of our white blood cells are generated in the bone marrow, with most being T-cells or T lymphocytes that help fight infections.

The central part of our bones (the endosteum) has active stem cells capable of transforming into various types such as liver cells, muscle tissue, cartilage, etc… These stem cells help to replace dying or damaged body tissues.

Bone marrow contains several types of stem cells: hematopoietic (for blood cell formation), spiral (capable of forming bone, cartilage & other types of connective tissues), and mesenchymal stem cells (for generating bone, fat, and tendon tissues).

where is bone marrow located:

bone marrow is a soft, spongy tissue that fills most of the hollow interior of bones. It comprises two types of cells: adipose cells called adipocytes and hematopoietic stem cells, which give rise to the other blood cells found in the body. For this reason, bone marrow is often called “the factory” or “the center.” Bone marrow produces new blood cells via a process known as hematopoiesis.

The production of these cells can increase dramatically during certain conditions, such as infection or medical treatment involving radiation therapy or chemotherapy. This leads to excess red blood cell formation (anemia) or thrombocytopenia, meaning a lack of platelets.

Other types of stem cells are also found in bone marrow, notably mesenchymal stem cells (MSC), the ability to give rise to the tissue of all germ layers. MSCs can be used in cell replacement therapy either by injection or grafting.

X-rays are used to examine the “empty” spaces inside bones since they do not pass through living tissue very well. Since there is no soft or connective tissue in these empty spaces, they appear white on an x-ray image under normal circumstances. Once cancer has developed in the marrow cavity, it shows on x-rays as patches of white space surrounded by irregular borders and masses with random, sharp edges.

Bone marrow can be affected by several diseases and disorders, including osteomyelitis, a bone infection; leukemia, a type of cancer caused by uncontrolled production of white blood cells; lymphoma, a different kind of cancer that originates in the lymphatic system; anemia due to lack of red blood cells; as well as some autoimmune diseases such as lupus erythematosus. Bone marrow transplants are now used to treat many previously incurable diseases.

in humans:

In human medicine, the primary role of bone marrow is to produce new blood cells from stem cells via hematopoiesis. In healthy adults, about 2% to 4% of bone marrow is occupied by red blood cells, which are produced in the process of erythropoiesis. The remaining marrow predominates in making two primary white blood cells, specifically lymphocytes and macrophages.

Lymphocytes are critical parts of the immune system, protecting against infections. Macrophages phagocytose debris and pathogens (bacterial, protozoan, or viral), as well as cellular waste material, play an essential role in inflammation.

Hematopoietic stem cells (also known as hemocytoblasts ) develop into multiple different cell types found in the blood and the immune system: myeloid progenitors become granulocytes, erythrocytes, or megakaryocytes  (which in turn produce platelets); lymphoid progenitors become T cells, B cells, NK cells, and mast cells.

The spleen is a secondary site for hemopoiesis. It filters the blood and removes old erythrocytes and excess leukocytes. The most significant portion of meconium is excreted through the umbilical cord. The kidneys help to excrete uric acid (a byproduct of cell degradation) into the urine.

what is a bone marrow transplant:

bone marrow transplantation (BMT) is a medical procedure in which the bone marrow cells and sometimes, rarely, other anatomic structures such as limbs or kidneys are replaced genetically.

Bone marrow transplantation is used to treat many diseases that severely affect the bone marrow’s ability to produce new blood cells. These include cancer, multiple myeloma, leukemia, Hodgkin’s disease, and sickle cell disease.

The most common type of BMT is allogeneic, meaning there is no genetic relationship between the donor and recipient. A related procedure known as syngeneic transplant treats autoimmune disorders like severe combined immunodeficiency disorder (SCID).

The patient receives their marrow in an autologous transplant (or auto-SCT). This is done with an eye toward future treatments, like high-dose chemotherapy, that might damage the healthy bone marrow.

Red bone marrow:

Red blood cells, or erythrocytes, are the most abundant cells in the blood. They contain hemoglobin, a complex chemical that binds to oxygen and makes it possible for red cells to assist gas exchange at the body’s tissues.

The primary function of red marrow is to produce new erythrocytes (red blood cells), but it also has white blood cells. In adults, more than 90% of erythrocyte production occurs here.

Besides being an essential site for erythropoiesis, red marrow is a rich source of hematopoietic progenitor cells capable of rescuing patients from lethal doses of radiation or chemotherapy.

Bone marrow transplantation is done by harvesting bone marrow from a donor and then transferring it into the host’s bone marrow.

This procedure aims to replace blood-forming cells destroyed by high doses of chemotherapy or radiation therapy with healthy new cells from a donor.  In some cases, as in autologous transplants, the patient receives their marrow after cancer treatment has killed off most or all of their old marrow.

The new marrow can come from either a related or an unrelated donor.  A related donor is usually a close family member, such as a brother or sister. An unrelated donor may be found through the National Marrow Donor Program.

Bone marrow symptoms:

The symptoms of bone marrow disease include:


neck pain or stiffness that gets worse when you move your neck from side to side,

hurt in a shoulder or arm that gets worse with movement and is made better by rest,

decreased range of motion of the neck or spine,

easy bruising or bleeding.

The most common cause of bone marrow disease is cancer. Other possible causes include Wegener’s granulomatosis, idiopathic thrombocytopenic purpura, myelodysplastic syndromes (such as aplastic anemia ), syphilis, and fungal infections, sickle-cell disease, autoimmune diseases such as rheumatoid arthritis and lupus.

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