Hematopoiesis

• 3 Phases of Hematopoiesis

  Mesoblastic phase

  Hepatic phase

  Medullary phase
• Nineteenth day of embryonic development after fertilization

  Mesoblastic ( Yolk sac) phase
• begins at 5 to 7 gestational weeks

  Hepatic (Liver) Phase
• fifth MONTH of fetal development

  Medullary ( Bone marrow) phase
• Other name of Mesoblastic phase

  Yolk sac phase
• Other name of Hepatic phase

  Liver phase
• Other name of Medullary phase

  Bone marrow phase
• Predominant Hemoglobin ( Hb) Mesoblastic phase

  Gower 1 ; Gower 2 ; Portland
• Predominant Hb of Hepatic phase

  Hb F
• Predominant of Medullary phase

  Hb A
• Location of hematopoietic tissue

  Bone marrow, lymph npdes, spleen, liver and thymus
• 2 components of BM


  Red marrow

  Yellow marrow
• Largest organs in the body

  Bone marrow
• Increased demand on the BM

  Yellow marrow
• Retrogession returns into _______

  RED MARROW
• Process of replacing the active marrow by

  adipocytes
• Development during yellow marrow

  Retrogession
• Broad, flat cells ; single CONTINUOUS LAYER

  Endothelial cells
• large cells with a SINGLE FAT VACUOLE

  Adipocytes
• functions in PHAGOCYTOSIS

  Macrophages
• bone FORMING cells

  Osteoblasts
• bone RESORBING CELLS

  Osteoclasts
• extend long, reticular fibers into perivasculad space

  Reticular adventitial cells
• CRITICAL ROLE in the regulation of hematopietic stem

  Stromal cells
• Major site of blood cell production

  Liver
• contains KUPFFER CELLS

  Liver
• outside the BM ; maintain hematopoietic action

  Extramedullary hematopoiesis
• largest LYMPHOID organ in the body

  Spleen
• Give the functions of Spleen


  storage site of 1/3 platelets.

  remove abnormal RBC.
• Give the 3 splenic tissue

  White pulp

  Red pulp

  Marginal zone
• Cords of Billroth


  Red pulp
• 2 methods for removing abnormal RBC

  Culling; Pitting
• End of product of pitting

  Bite cell
• Degradtion of cell organelle ( kakainin macrophage)

  Culling
• remove inclusions or damaged surface membrane ( kakagatan macrophage)

  Pitting
• Important in T & B cell development

  Lymph nodes
• Important for the bone marrow maturation

  Thymus
• Non development of thymus

  Di- George Syndrome
• Thymus divided into 2:

  Cortex ( Peripheral zone)

  Medulla ( central zone)
• From the BM to thymus called

  T- cell maturation