BIOL 030 Lecture Notes - Lecture 25: Hematopoietic Stem Cell, Bone Marrow, Yolk Sac
17 Sep 2020
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Adult production of 400 billion platelets, 100-200 billion rbcs, and 10 billion wbcs every day. Embryo: yolk sac produces stem cells for first blood cells. Colonize fetal bone marrow, liver, spleen, and thymus. Liver stops producing blood cells at birth. All formed elements originate from pluripotent stem cells (ppsc) (a. k. a. hemocytoblasts or hemopoietic stem cells) Functions: carry oxygen from lungs to cell tissues, pick up co2 from tissues and bring to lungs. Insufficient rbcs can cause death in minutes due to lack of oxygen to tissues. Cytoskeletal proteins (spectrin and actin) give membrane durability and resilience. Stretch and bend as squeezed through small capillaries. Adult hb has 2 and 2 chains. Globins bind co2 (5% of co2 in blood) Heme groups non-protein moiety that binds o2 to iron (fe) at its center. Conspicuous nuclei violet to dark purple in blood stains. Phagocytosis of antigen antibody complexes, allergens, and inflammatory.
