1. Hemostasis (Hemo-blood Stasis-standing still)
Stoppage of bleeding resulting from a break in a blood vessel
Hemostasis involves three phases
1. Vascular spasms
2. Platelet plug formation
3. Coagulation (blood clotting)

2. Step One: Vascular spasms
Vasoconstriction causes blood vessel to spasm
Spasms narrow the blood vessel, decreasing blood loss

3. Step 2: Platelet plug formation
Collagen fibers are exposed (because of the break in a blood vessel

4. Step 2: Platelet plug formation
Chemical signals cause the platelets to become activated (sticky) and cling to collagen fibers
Anchored platelets release chemicals to attract more platelets
Platelets pile up to form a platelet plug

5. Step 3: Coagulation Injured tissues release tissue factor (TF)
protein clotting factors and calcium ions trigger a clotting cascade

6. prothrombin is activated
prothrombin to thrombin (an enzyme)
thrombin builds fibrinogen proteins into hair-like molecules of fibrin (insoluable)
fibrin forms a meshwork (the basis for a clot)

7. Hemostasis Blood usually clots within 3 to 6 minutes
The clot remains as endothelium regenerates
The clot is broken down after tissue repair