Haemostasis Flashcards
List the 4 components for haemostasis
1) Vascular response
2) Primary haemostatic plug
3) Secondary haemostatic plug
4) Total lysis of clot
Define the first component for haemostasis
Vascular response
Vasoconstriction
Define the second component for haemostasis
Primary haemostatic plug
Platelet plug forms
Define the third component for haemostasis
Secondary haemostatic plug
Fibrin clot forms on platelet plug
Define the fourth component for haemostasis
Final component
Total lysis of the clot
Clot is lysed and parts are taken back up into blood stream
How is the primary haemostatic plug formed?
Platelet ADHESION
Platelets stick together at damaged site
Platelet ACTIVATION
Platelets exposed to collagen from endothelium
—> change shape
Platelet SECRETION
Release chem’s to increase number of platelets gathered at site
Platelet AGGREGATION
Platelets clump together
What is a sciency word for platelet?
Thrombocyte!
THROMBO - like clot
Clot cell :)
Which pathway is activated by collagen exposure?
Intrinsic pathway is activated by _____ exposure
Which pathway is activated by exposure to tissue factors?
Extrinsic pathway
Tell me about the INTRINSIC Pathway
Activated by collagen exposure
Vascular injuries
Endothelial injuries - damaged blood vessel
Tell me about the EXTRINSIC Pathway
Activated by tissue factors
Tissue factors are released extravascularly from tissue injuries
How is the Secondary Haemostatic Plug formed?
Plasma proteins which are present in the blood in their inactive form are activated by one of two pathways
Tissue - Extrinsic
Vascular - Intrinsic
Fibrin mesh forms to strengthen clot
Which type of Haemophilia is more common?
Haemophilia A is most common - 85-90% of all cases
Haemophilia B is least common - 10-15% of all cases
What happens in the fourth stage of haemostasis
Total lysis of the clot = Fibrinolysis
To maintain blood in its liquid form
Endothelial cells release Plasminogen
Plasminogen —-> Plasmin
—-> Clot lysis
—-> Fibrin degradation products go back into bloodstream
