Hematopoiesis

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Hematopoiesis Hemostasis
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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

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(2) Red Blood Cell Development

• RBCs 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

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(3) Rate of RBC Production

• (Erythropoeitin Release ? More RBCs)
• 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
• RBCs produced

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(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!

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• 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 RBCs.
• Vessels Constrict and ruptured edges are closed
  together.

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Thromboplastin.
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Prothrombin.
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Thrombin.
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Fibrinogen.
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Fibrin.
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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
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(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.

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(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.

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(7) Hemophilia

• (Hemostatic Disorder)
• Low Clotting Factor Count Slow Clotting Rate
• Either missing Clotting Factor 8 or 9

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