Hemostasis Flashcards
Process by which the body stops bleeding only at the site of blood vessels injury and maintains blood in the FLUID STATE in the vascular compartment.
Hemostasis
2 phases of Hemostasis:
Primary and Secondary Hemostasis
Vascular and platelet response to vessel injury
Primary Hemostasis
Response of a coagulation process to such injury
Secondary Hemostasis
Activated by desquamation and small injuries to blood vessels
Primary Hemostasis
Involves vascular intima and platelets
Primary Hemostasis
Rapid, short-lived response
Primary Hemostasis
Activated by large injuries to blood vessels and surrounding tissues
Secondary Hemostasis
Involves platelets and coagulation system
Secondary Hemostasis
Delayed, long-term response
Secondary Hemostasis
Factors included in Primary Hemostasis:
- Blood vessels
- von Wilebrand factor
- Fibrinogen
- Calcium
- Platelet
3 hemostatic components
- Extra-vascular
- Vascular
- Intra-vascular
Plays a part in Hemostasis by
providing back-pressure on the injured vessel through swelling and trapping of escaped blood.
Extra-vascular
Key mediator of the vasoconstriction
Thromboxane A2
Process by which blood is converted from the liquid to solid state, namely the fibrin clot.
Coagulation
Prime functions of Hemostasis
- Maintain blood in fluid state
- Arrest bleeding followed by trauma
- remove platelet plug when healing is complete
Steps (components) of Hemostasis
- Vasoconstriction
- Platelet adhesion
- Platelet aggregation
- Fibrin-platelet plug formation
- Fibrin stabilization
Neurogenic response
Vasoconstriction
Release of tissue thromboplastin
Extrinsic coagulation pathway
Initiated by protein factors found circulating in the blood
Intrinsic Coagulation Pathway
Initiated by protein factors located in the tissues
Extrinsic Coagulation Pathway
Process that occurs once the fibrin clot has formed
Retraction
Involves contraction and shrinkage of the fibrin strands and is induced by continued release of Factor XIII from platelets
Clot Retraction
Serves to pull the edges of the damaged blood vessel together to facilitate the repair process
Clot retraction
Accomplished by the enzyme plasmin that digests the fibrin
strands of the clot as well as several clotting factors.
Fibrinolysis or Clot dissolution
Inhibits factor X and thrombin
Antithrombin III
