1. Hematopoiesis and Blood Clotting
Anatomy and Physiology

2. Hematopoiesis Blood cell formation
Occurs in red marrow (myeliod tissue)
Skull and pelvis
Ribs
Sternum
Proximal epiphyses humerus and femur
One ounce/day (1 billion cells)

3. Cell Formation All arise from hemocytoblast
Once it starts type is committed
Second generation
Lymphoid stem cell (lymphocytes)
Myeloid stem cell (all other formed elements)

4. RBC Formation Anucleate so they don’t grow or divide
Last between days
Remains removed in spleen, liver, etc
Cell division in red marrow replaces them
When mature nucleus & organelles ejected
Creates reticulocyte (immature)
2 days to mature 3-5 total

5. RBC Homeostasis Controlled by hormone erythropoietin
Produced mainly in the kidney
O2 levels determine levels not number of cells!

6. Formation of WBC’s and Platelets
Also hormonally controlled
WBC’s
Colony stimulating factors (CSF’s)
Interleukins
Platelets
thrombopoietin

7. Hemostasis Blood standing still Fast and localized
Uses many substances normally in the blood and a few others
Vascular spasms
Platelet plug formation
Coagulation
Fibrous tissue seal

8. Hemostasis 1. Vascular Spasm Vasoconstriction Decreases blood flow
Direct injury
Pain receptors
Serotonin release
2. Platelet Plug Formation
Stick to collagen
Release serotonin

9. Continued Coagulation Injured tissue release TF
PF3 reacts with TF, vitamin K and clotting factors and Ca2+
Triggers cascade
Clot retracts bringing edges together

10. Clotting Information 3-6 minutes
Cascade deactivated rapidly to keep the clotting localized
Clot is broken down when tissue heals
How do we help clotting along?
Pressure
Gauze

11. Homeostatic Imbalance
Thrombus (stationary clot)
Embolus (moving clot)
Caused by
rough endothelium
Fatty deposits
Slow blood flow
Prevented by
Aspirin
Heparin
Dicumarol (Coumadin)

12. Bleeding Disorders Thrombocytopenia Liver problems Hemophilia
Low platelets
May cause petichiae (small purple blotches)
Liver problems
Low vitamin K
Hepatitis/Cirrhosis
Hemophilia
Hereditary lack of clotting factors
Fresh plasma or pure clotting factors
AIDS linked to blood products in past