Haematopoiesis

Haematopoiesis is the process by which the body produces all types of blood cells. This process takes place in the bone marrow, the soft fatty tissue inside bone cavities. Two types of stem cells are found in the bone marrow: hematopoietic stem cells and stromal stem cells.

Process

Haematopoiesis involves the differentiation and proliferation of stem cells into mature blood cells. It is a complex process regulated by various growth factors and cytokines. The process begins with a pluripotent (undifferentiated) stem cell, which undergoes several stages of differentiation, guided by the body's needs, to become a mature, functional blood cell.

Types of Blood Cells

There are three types of blood cells produced by haematopoiesis:

• Erythrocytes or red blood cells, which carry oxygen to tissues
• Leukocytes or white blood cells, which fight infection
• Platelets, which are involved in clotting

Regulation

The regulation of haematopoiesis involves complex interactions between the cells and their environment, known as the hematopoietic microenvironment. This includes the bone marrow stroma, which contains supporting cells and extracellular matrix, and a variety of growth factors and cytokines produced by the cells themselves.

Disorders

Disorders of haematopoiesis can lead to a number of serious conditions, including leukemia, anemia, and myelodysplastic syndromes. These disorders can result from abnormalities in the proliferation or differentiation of hematopoietic stem cells.

See Also

• Hematopoietic stem cell transplantation
• Bone marrow transplant
• Stem cell therapy

Haematopoiesis

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  Hematopoiesis simple
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  Hematopoesis EN
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  Hematopoiesis (human) diagram en
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  Hematopoietic growth factors