Ch15-1 Lateral plate mesoderm

Need the stem cellThe concept of stem cells Everyday, about 10 11 red blood cells are killed inthe spleen, and need to be replaced. The replacements come from populations of stemcells. A stem cell is a cell that is capable of extensive proliferation,creating more stem cells (self-renewal) as well as moredifferentiated cellular progeny.Hematopoietic stem cell (HSC) is critical in hematopoiesis.Differences in hematopoiesisSites Of Embryonic Hematopoiesis Two Phases:Transient embryonic “primitive” phaseDefinitive “adult” phase Different Phases differ in Sites of blood production Timing of hematopoiesis Type of globin genes in red blood cells Blood islands in the ventral mesoderm near the yolksac. Visceral (splanchnic) lateral plate mesoderm nearthe aorta, the aorta-gonad-mesonephros (AGM)region. PlacentaBMP2 & BMP4 are critical in inducing the bloodforming cells.Hematopoiesis in the aorta-gonad-mesonephros(AGM) regionTransition of sources of blood cells to the bonemarrow3-Day chick embryoHematopoietic Stem Cell, HSCThe hematopoietic stem cells colonize the fetal liver, and the stemcells from the liver populate the bone marrow.AortaHSCHSCHSCHSCChemo-attractant proteins for HSC, which are secreted from thebone and spleen and attract into them.