Erythropoiesis

Erythopoiesis is production of RBC. It is occur at beginning of intrauterine life in yolk sac. After that
liver and spleen produce RBC in the fetus. At birth all bones of the body involve to production of RBC and the person become adult axial skeleton ( Sternum,Ribs,Pelvis,Vertebrae ) and proximal ends of long bones (Femur & Humerus ). 

Erythopoiesis starts from pluripotent uncomitted stem cells. This cells undergoes three steps to become mature RBC. They are,

• Proliferation

• Differentiation

• Maturation  

                                                          After series of differentiation pluripotent uncomitted stem cell become late normoblaste. It contain 34% of Hb and it expel the nucleus and become Reticulocytes. Reticulocytes still contain mRNA. So it still can produce Hb. Finally it become mature RBC. Mature RBC haven't any nucleolus, mitochondria and release to normal circulation.

Normal RBC concentration in male 3.9-5 * 10¹² /L. In female 4.5-6 * 10¹²/L.

Process of erythropoiesis needs 

• nutrients ( Fe, Vit. B₁₂,Folic acid) 
• hormones ( Thyroxin, Androgen ) 
• Microelements (Cu2+,Zn,Co,Mn,Vit.C,Vit.E,Vit.B₆,Thiamin, Riboplavin,Pantothenic acid) 
• Micro environment ( Fibroblasts, Macrophages,Collagen).