1. vessel wall: endothelial cells

2. platelets: cell fragements from bone marrow megakaryocytes that form heostatic plug

3. plasma proteins: coagulant proteins, anticoagulant, proteins, fibrinolytic proteins

1. vascular phase

2. platelet phase

3. coagulation phase

4. fibrinolytic phase

the initial trigger to activate hemostatic processes

- tissue injury causes smooth muscle cell contraction

-lasts 5-20 minutes

Describe the platelet phase.

(lengthy)

platelets circulate in an inactivated state; they do not normally adhere to the vascular wall

adherence: binding to subendothelial collagen and vWF is mediated by receoptors on platelets

activation: mediated by adhesion and gonists that are released from endothelial cells and other plts

- activation of thromboxane, thrombin and collagen receptors on plts lead to secretion of granule contents

granule secretion: mult factors including ADP

adherence

activation

activation includes thromboxane, thrombin, and collagen receptors on platelets being occupied, leading to secretion of granule contents

I do these three things:  

1. induce release of granule contents

2. increase expressionof GPIIB/IIIA

3. stimulate plt activation

who am I?

Thromboxane A2 (TXA2)

-producuded in platelets

clotting cascade is activated ultimately resulting in the formation of a fibrin clot