Answer:
System of creating new blood cells is called hematopoiesis
EXPLANATION:-
- Haemtapoesis is process by which cellular components of blood are formed.
- In adults site where haematopoesis takes place is Bone Marrow.Here Multipotent hematopoetic stem cells are present(HSCs).
- In the prenatal stage, haematopoiesis occurs in the yolk sac during the first weeks of embryonic development and transitions to the spleen, liver, lymph nodes and finally in the bone marrow continuing for lifetime.
PROCESS OF HEMATOPOESIS
- HSCs divide generating daughter cells. Some daughter cells retain the stem-cell characteristics of the mother cell having property of self self-renewing and able to give rise to all blood cell types. While other daughter cells differentiate into progenitor cell that lose their self-renewal capacity and giving rise to a particular blood cell lineage.
- Therefore, early in hematopoiesis, a multipotent stem cells differentiates along one of two pathways, giving rise to either a common lymphoid progenitor cells or a common myeloid progenitor cells.
- Then, relying upon the cytokines and resulting transcription factors that are activated, the myeloid progenitor can differentiate into a myeloblast.
- This myeloblast leads to granulocyte (basophils, eosinophils, or neutrophils) or monocyte (macrophages and dendritic cell) development.
- Also, it leads to the differentiation of megakaryocytes into platelets, or erythroblasts into erythrocytes.
- Lymphoid dendritic cells can form directly from the common lymphoid progenitor.
- Furthermore, the differentiation of the common lymphoid progenitor into a lymphoblast results the further development of natural killer cells or lymphocytes (T and B cells).
- Once B cells get activated in secondary lymphoid organs, it further differentiate into plasma cells.
- These plasma cells secrete antibodies.
Regulation of Haematopoiesis:
Hematopoiesis is largely regulated by the presence of cytokines.
These cytokines are responsible for regulating the differentiation of multipotential hematopoietic stem cells into specific cell types by the activation of transcription factors.
The cytokines is very important for differentiation of particular cell types otherwise animal dies during embryogenesis.