Platelets, coagulation and bleeding Flashcards
What are the components primary hemostasis?
-Platelets
What are the components of secondary hemostasis?
-Coagulation cascade-fibrin formation
What converts fibrinogen (Soluble) to fibrin (insoluble)?
-Thrombin
What is the intrinsic pathway measured by?
-PTT (Patrial thromboplastin time)
What are vitamin K-dependent factors?
- II
- VII
- XI
- X
What is a normal PTT?
25-35 seconds
What does PT (Prothrombin Time) measure?
-Extrinsic pathway
What is a normal PT?
11-13.5 seconds
What are the features of platelets?
- Anucleated
- 10 day lifespan
- Circulating platelets do not adhere it is during stasis adhesion occurs
How id primary hemostasis initiated?
-Injury
In primary hemostasis adherence to subendothelium occurs by interaction with what?
-Von Willebrand factor (Carrier for factor VIII)
Secondary hemostasis factors are mostly from where?
-Liver
What are the factors in the intrinsic pathway?
- XII
- XI
- IX
- VII
What are extrinsic pathway factors?
- VII
- IX
What are common pathway factors?
- X
- V
- II
- Fibrin production
What tests are used to measure the common pathway?
PT and PTT
What do fibrin and platelet aggregates form?
-Stable clot