BIOL130 Lecture Notes - Osteoclast, Heterochromatin, Cd90
28 Jan 2013
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Vasculogenesis de novo formation of blood vessels during fetal life. 1) embryonic splanchnic mesoderm mesenchyme angioblasts angioblasts fuse to form endothelial cords angioblasts endothelial cords differentiation involves vegf expression by endoderm. 2) angioblasts in cords endothelium (also requires vegf) lumen forms. 3) cords coalesce in yolk sac and embryo primary endothelial plexus. Mesoblastic (blood cells from yolk sac, chorion) 2 2 develop within blood islands of developing vessels blood islands. Hepatic (1/2 of all liver cells are rbc precursors) fetal hemoglobin higher oxygen affinity than adult liver/spleen secrete erythropoetin. Myeloid (accounts for most blood cell production at birth) , begins lymphocyte production. Postnatal hematopoesis proceeds from a single hematopoetic pluripotent stem cell (hsc) characteristics: Unidirectional division myeloid lineage formed in bone marrow. Hsc evidence for existence: lethally irradiated mice rescued by injection of bone marrow. Hematopoetic cell colonies count on spleen was proportional to amt. of marrow injected.
