Erythropoiesis | Anatomy2Medicine


    • In the early weeks of embryonic life, primitive, nucleated red blood cells are produced in the yolk sac. (MCQ)
    • During the middle trimester of gestation, the liver is the main organ for production of red blood cells (MCQ)
    • During the last month or so of gestation and after birth, red blood cells are produced exclusively in the bone marrow.
    • the bone marrow of essentially all bones produces red blood cells until a person is 5 years old.
    • The marrow of the long bones, except for the proximal portions of the humeri and tibiae, becomes quite fatty and produces no more red blood cells after about age 20 years. (MCQ)
    • Beyond 20 years age, most red cells continue to be produced in the marrow of the membranous bones, such as the vertebrae, sternum, ribs, and ilia.
    • interleukin-3, promotes growth and reproduction of virtually all the different types of committed stem cells (MCQ)


  • Stages of Differentiation of Red Blood Cells
  • The first cell that can be identified as belonging to the red blood cell series is the proerythroblas


    • The first-generation cells are called basophil erythroblasts
    • Because of the short life of the reticulocytes, their concentration among all the red cells of the blood is normally slightly less than 1 per cent.


  • Regulation of Red Blood Cell Production—Role of Erythropoietin


    • Tissue Oxygenation Is the Most Essential Regulator of Red Blood Cell Production.
    • Erythropoietin
      • Stimulates Red Cell Production
      • Its formation Increases in Response to Hypoxia.
      • 90 per cent of all erythropoietin is formed in the kidneys; the remainder is formed mainly in the liver. It is not known exactly where in the kidneys the erythropoietin is formed. (MCQ)
      • important effect of erythropoietin is to stimulate the production of proerythroblasts from hematopoietic stem cells in the bone marrow.  (MCQ)