04. Adult Stem Cells

• haematopoietic stem cells are generated first at the aorta-gonad-mesonephros region at the ventral wall of the dorsal aorta

  • epithelium undergoes endothelial to haematopoietic transition

  further expansion then occurs in the foetal liver and then the bone marrow
• long term hscs can fully self renew and maintain or even expand the pool of long term hscs, but short term hscs have differentiation outweigh their self renewal
• hscs are largely quiescent even though humans generate lots of new blood cells every day
• hsc niche = bone marrow

  • likely involves perivascular cells, endothelial cells, macrophages and oxygen
• mesenchymal cells = multipotent bone marrow stromal cells

  • surround blood vessels
  • act as feeder layer for hscs in vitro
  • can form bone, fat and cartilage
• mesenchymal stem cells are below intestinal crypt cells

  • bottom = wnt signalling and bmp inhibition
• neuroblasts = neural stem cells

  • delaminate from neuroepithelia
• ganglion mother cells = neural precursors