Hematopoiesis – Overview
Hematopoiesis, also known as Hemopoiesis is formation and development of blood cells. Meaning of the term hematopoiesis is “Hemo = blood” and “poiesis = to form”. Hematopoiesis occurs in bone marrow.
The starting point of Hemopoiesis is Hematopoietic Stem Cell (HSC) which is a pluripotent stem cell. What is pluripotent now?? The meaning of pluripotent is “pluri = several” and “potent = being able” which means the cell has ability to differentiate or give rise to several different types of cells.
The first differentiation of HSC results in two lineages – Myeloid stem cell and Lymphoid stem cell.
Myeloid stem cells differentiates into three progenitor cells – Colony Forming Unit – Erythrocyte (CFU-E), Colony Forming Unit – Megakaryocyte (CFU-Meg) and Colony Forming Unit – Granulocyte and Macrophage (CFU-GM). Once the progenitor cells are formed, the next stage is the formation of precursor cells (suffix “blast” will be applied in all precursor cells). So from CFU-E, proerythroblast will form. From CFU-Meg, megakaryoblast will form. From CFU-GM two precursor cell will form as the term suggest, monoblast and myeloblast and there will be two more precursor cells directly differentiating from myeloid stem cell and they are eosionophilic myelolast and basophilic myeloblast.
Lymphoid stem cells differentiates into two progenitor cells, i.e. prothymocyte and pre B-cell and they will develop into precursor cells T lymphoblast and B lymphoblast respectively. Here also there is one direct precursor cell formation without the progenitor cell stage and that is NK lymphoblast.
To read a blog post on this topic here which can be your quick short note.