ERYTHROPOIESIS
Erythropoiesis is the process that creates red blood cells. In unipotent stem cells, proerythroblast differentiation is stimulated. The proerythroblasts undergo multiple stages of division, each of which produces a more advanced cell type.
Eventually, the cells will stop dividing and will become nucleated. They also start producing haemoglobin. After this, red blood cells (RBCs) must go through three more phases of maturation before they are fully developed. For dogs, the entire process takes about one week; for cows, it takes about four to five days; and for birds, it takes about 36 hours.Hormones, primarily erythropoietin (EPO), and the availability of iron, folic acid, vitamin B12, protein, and other components required to form red blood cells regulate the rate of erythropoiesis. The primary source of erythropoietin is the peritubular interstitial cells found in the kidney. Erythropoietin synthesis in the kidney is controlled by blood oxygen levels. Hypoxia is the cause of increased erythropoietin production. Erythropoietin stimulates erythropoiesis in the red bone marrow because a variety of diseases may result in tissues having less oxygen available to them. In cases of severe anaemia, nucleated red blood cells (NRBCs) may be released. Nucleated red blood cells (RBCs) are immature red blood cells that still contain their nuclei.They are not fully matured, so even though they are producing some haemoglobin, their efficiency is reduced (Table 6.1)
6.9