Hematopoiesis Flashcards
what is hematopoiesis
development from hematopoietic stem cells, that generates blood cells
where are HSC found?
in the bone marrow of mammals
how are erythrocytes disposed?
they are phagocytosed by macrophages in the spleen
what is a stem cell?
a cell that can proliferate extremly well, is self renewing, can differentiate into atleast 2 cell types, can reconstitute tissues after injury
what are the different types of stem cells
totipotent, and multipotent
totipotent stem cell
can generate an entire organism
multipotent stem cell
can differentiate into several different cell types
HSC’s are
multipotent
HSC daughter cells can be
myeloid and lymphoid prognitor cells
myeloid cells can give rise to
megacariocytes, erythroid cells, granulocytes, monocytes
lymphoid cells can give rise to
T and B lymphocytes, and NK cells
what are the hematopoietic organs in a child and in an adult
child: whole body
adult: axial skeleton
what are hematopoietic growth factors
are cytokines that stimulate the progenitor cells and induce proliferation and maturation. They are glycoproteins.
name the hematopoietic cytokines
- erythropoietin: differentiation of RBC
- CSF: can stimulate macrophages, granulocytes, monocytes in culture
- IL7: diff. of lymphocytes
- IL3: diff. of stem cells
- LIF: survival of stem cells
- SCF: diff. of stem cells
what is the mechanism of action of cytokines?
- lineage restricted
- action on multiple lineages
where do the cytokines come from?
kidney released EPO
vessels release M-CSF
lungs, muscles, thymus, bladder release GM-CSF
what does a cytokine signal?
- functional stimulation
- survival
- proliferation
- maturation
- differentiation
what cells and molecules are part of the hematopoietic niche
- CAR cells
- endothelial cells: for sinusoids and arterioles
- CXCL12: chemokine which binds t CXCR4 and is a retention signal
- SCF
HSC’s transplantation is of 4 types
- autologous: stem cell harvested from self
- allogenic: stem cells harvested from donor
- syngeneic: stem cell harvested from identical twin
- cord blood: stem cells saved from cord blood from self or donor
