What Are the Different Types of Bone Marrow?

Bone marrow exists in the cancellous cavity of bone and long bone marrow cavity. It is composed of many types of cells and reticular connective tissue. It is divided into red bone mar-row and yellow bone marrow ( yellow bone marrow). For soft and bloody tissue.

Bone marrow exists in the cancellous cavity of bone and long bone marrow cavity. It is composed of many types of cells and reticular connective tissue. It is divided into red bone mar-row and yellow bone marrow ( yellow bone marrow). For soft and bloody tissue.

Chinese name

marrow

Foreign name

bone marrow

Specific

Hematopoietic tissue

Classification

Red and yellow bone marrow

Pinyin

g su

Bone marrow classification

Adult bone marrow is one of the largest organs in the human body, 1600 to 3700 grams, with an average of 2800 grams, accounting for 3.5 to 5.9% of body weight. Bone marrow has hematopoietic, immune and defense functions.

Red bone marrow

Red bone marrow is the hematopoietic organ of the human body and is distributed in the bone marrow cavity. It also contains a small amount in the Harvard's canal. It is mainly composed of blood sinus and hematopoietic tissue. Sinus sinus is a sinus-shaped space formed after the branching of arterial capillaries into the red bone marrow. It has an irregular shape and different diameters. The sinus wall is lined with endothelial cells, with basement membranes and pericytes attached to the outside. Hematopoietic tissue is located between the sinusoids. Its matrix is reticular fibers and reticular cells, which form a network frame. The pores are filled with various free cells, such as various blood cells and mesenchymal cells at different developmental stages. In the newborn period, all bones are filled with red bone marrow, which has an active hematopoietic function. In adulthood, the red bone marrow is mainly present in the epiphysis of some flat, irregular and long bones. The vertebrae, sternum and sacrum are most abundant, and the hematopoietic function is also most active.

In addition to the hematopoietic function, the red bone marrow also has various functions such as defense, immunity and wound repair. Its wound repair function is mainly due to the immature mesenchymal cells, which retain the potential to differentiate into fibroblasts and osteoblasts. Some scholars have used bone marrow stromal cells cultured from red bone marrow to implant fractures and bone defects, and they have proven that they can promote the formation of bone tissue, which is beneficial to fracture healing and defect repair.

2. The bone marrow cavity of young children is all red bone marrow. After 5 years old, the red bone marrow in long bones is gradually replaced by adipose tissue and becomes yellow bone marrow. After the age of 18, the long bones of the body were almost filled with yellow bone marrow. Red bone marrow and yellow bone marrow account for half of normal adults. Red bone marrow is distributed in the cancellous bones of the flat bones (skull, sternum, ribs, sacrum), vertebrae, collarbone, scapula, and long bones. Older people's bone marrow turns into fat-deficient mucus-like marrow. Yellow bone marrow contains a large amount of adipose tissue. Although it does not have hematopoietic function, it still contains a small number of naive hematopoietic cell clusters, maintaining its hematopoietic potential. Under certain pathological conditions, the yellow bone marrow can be re-transformed into red bone marrow with hematopoietic function.

Yellow bone marrow

The yellow bone marrow is mainly composed of adipose tissue, that is, the stromal cells of the bone marrow become a large number of adipocytes, with only a small number of naive cell clusters, and its hematopoietic function is weak.

Adult red bone marrow produces red blood cells, granulocytes, platelets, and some lymphocytes.

Many factors are involved in the regulation of bone marrow hematopoietic function: the reduction of oxygen in the blood stimulates the formation of red blood cells; the same high-altitude life increases the red blood cells; blood loss enhances the mitosis of the cells in the bone marrow; the protein in food promotes the formation of red blood cells; Vitamin B2 must be present during normal formation.

Yellow bone marrow can turn into red bone marrow when adults are highly anaemic and lose blood.

Histological structure of bone marrow

Bone marrow cells are a general term for various cells in the bone marrow (mainly red bone marrow). Bone marrow is the main hematopoietic organ, producing red blood cells, granulocytes, monocytes, lymphocytes, and platelets. Therefore, bone marrow cells include cells of different developmental stages of various blood cell lines, and their components are more complex. Such as granulocyte cell lines, which account for about 40% to 60%, including promyelocytic cells, promyelocytic cells, mesenchymal cells, late promyelocytic cells, baculoblasts, and lobulated neutrophils; lymphocyte lines account for about 20 %, Including prolymphocytes, prolymphocytes, and lymphocytes; red blood cell lines account for about 20%, including proerythroblasts, early and young red blood cells, young and red blood cells, late red blood cells, reticulocytes, and red blood cells; mononuclear cell lines account for about 4 %, Including original monocytes, juvenile monocytes, and monocytes; megakaryocytes account for about 4%, including promegakaryocytes, juvenile megakaryocytes, and megakaryocytes, and finally form platelets; plasma cell lines include protoplasma and cytoplasm Cells and plasma cells. In addition to the above hematopoietic cells, the bone marrow contains other cells, such as reticulocytes, endothelial cells (phagocytic cells), and so on. Certain chemicals (such as benzene) can inhibit the ability of bone marrow cells to divide and proliferate, causing leukopenia, thrombocytopenia, aplastic anemia, or stimulating excessive proliferation of granulocyte cell lines to induce leukemia.

Bone marrow related technology

Bone marrow transplantation: Bone marrow transplantation includes allogeneic and allogeneic transplantation. Allogeneic transplantation only occurs between identical twins, while allogeneic transplantation refers to transplantation between different individuals. Therefore, usually, bone marrow transplantation mainly refers to allogeneic transplantation.

But not all people with leukemia are suitable for bone marrow transplants. Bone marrow transplantation is only suitable for patients who are not sensitive to chemotherapy. They need to use normal human immune cells to kill drug-resistant cancer cells and rebuild blood function. And bone marrow transplantation should be treated separately for different situations. The earlier the transplantation of highly dangerous patients, the better the effect. When no HLA-matched donor can be found, blood-related HLA semi-matched transplantation can save the lives of some patients in time.