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Hematopoiesis & Hemostasis. (1) Hematopoiesis. Blood Cell Formation Occurs in Red Bone Marrow Cell Development:. Hemocytoblast (original stem cell). Lymphoid Stem Cell. Myeloid Stem Cell. Erythrocytes Basophils Eosinophils Neutrophils Monocytes Platelets. Lymphocytes.
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(1) Hematopoiesis • Blood Cell Formation • Occurs in Red Bone Marrow • Cell Development: Hemocytoblast (original stem cell) Lymphoid Stem Cell Myeloid Stem Cell • Erythrocytes • Basophils • Eosinophils • Neutrophils • Monocytes • Platelets • Lymphocytes
(2) Red Blood Cell Development • RBC’s have no nucleus… • Synthesize hemoglobin during development • Increase in hemoglobin Eject Organelles • Results in Biconcave Shape • Erythropoeitin:Protein which controls rate of RBC production. • Circulates in blood • Targets bone marrow • Produced in liver + kidney • Decrease in Oxygen Increase in Erythropoeitin
(3) Rate of RBC Production (Erythropoeitin Release More RBC’s) • Stimulus: • Change in RBC count • Change in Oxygen availability • Change in demand for Oxygen • Scenario: Decreased RBC count… • Reduced Oxygen in blood • Kidney releases erythropoeitin • Red bone marrow stimulated • RBC’s produced
(4) Hemostasis (Blood Clotting) • Stimulus: Injury to blood vessel. • Events: 1. Collagen fibers exposed, Platelets adhere. 2. Platelets release serotonin to constrict vessels, More platelets seek wound. 3. Thromboplastin released by damaged vessel cells. 4. PF3 (Phospholipid) binds with Thromboplastin + Calcium BEGIN CLOTTING CASCADE!
Clotting Cascade (Prothrombin Activator): • Prothrombin converted to Thrombin. • Thrombin joins Fibrinogen proteins to form larger polymer (Fibrin). • Fibrin forms a mesh-like trap to catch RBC’s. • Vessels Constrict and ruptured edges are closed together.
Initial Injury Clotting Cascade Begins Prothrombin changed to Thrombin by Prothrombin activator Thrombin binds with Fibrinogen to form Fibrin… Finally the mesh-like net is formed to catch blood cells
(5) Thrombus vs. Embolus • Thrombus Clot in wall of blood vessel • Embolus Free Floating Thrombus • Causes: • Rough blood vessel tissue from burns, ruptures, fat. • Slow blood flow (low levels of activity) • Aspirin: Common over the counter anticoagulant.
(6) Thrombocytopenia (Hemostatic Disorder) • Low platelet count & Slow Clotting Rate • Typical of bone marrow cancer and/or radiation patients. • Caused by damaged liver Cannot make clotting factors.
(7) Hemophilia (Hemostatic Disorder) • Low Clotting Factor Count & Slow Clotting Rate • Either missing Clotting Factor #8 or #9