Hematopoiesis Flashcards
process of blood cell production, differentiation, and development.
Hematopoiesis
Hematopoietic system consists of:
●bone marrow
●liver
●spleen
●lymph nodes
●thymus
proliferation and differentiation of red blood cells
Erthyropoiesis
development of whute blood cells
Leukopoiesis
Development of platelets
Thrombopoiesis
the foundation of the adult hematopoietic system
Hematopoietic Stem Cells (HCSs)
Three types of Human Stem Cells
- Totipotential stem cells
- Puripotential stem cells
- Multipotential stem cells
●cells present in the first few hours after an ovum is fertilized.
●versatile type and can develop into any human cell type, including development from embryo into fetus
Totipotential stem cells
●cells are present several days after fertilization.
●can develop any cell type, except into a fetus
Pluripotential stem cells
●cells derived from pluripotent stem cells.
●found in adults, but limited to specific types of cells to form tisues
Multipotential Stem Cells
Yolk sac phase
Mesoblastic
Liver phase
Hepatic
Bone marrow phase
myeloid
3rd week of gestation, these cells aggregate into cluster of cells known as “blood island”
Mesoblastic Period
This phase occurs intravascularly, or within a developing blood vessel. it remains active until 8-12 weeks of gestation.
Mesoblastic period
Arise from mesodermal cells, which initially line the cavity of the yolk sac
Immature cells: Primitive Erythroblasts
Globin chains produced:
- Epsilon
- Zeta
- Gamma
Embryonic forms of hemoglobin:
- Gower I
- Gower II Portland
Hepatic period begins at ______ week of gestation and remain active unril 1st lr 2nd week after birth
5th ans 6th
this phase occurs extravascularly, with the liver remaining the major site during fetal life and retaining activity until 1 to 2 weeks after birth.
Hepatic Period
first fully developed organ in the fetus, becomes the major site of T-cell production
Thymus
kidney and spleen produce?
B cells
5tt of week gestation, bone cavities begin to assume the responsibility as the mainnsite of blood cell production
Myeloid/Medullary Period