Haemostais Flashcards
What is primary Haemostasis
The formation of the initial platelet flot
What are the steps in primary Haemostasis
Initial vasoconstriction
Thromboxane stimulation (attracts the platelets)
Granules come (ADP, PAF, fibrinogen)
Stimulation of Gbllb/lla (by ADP) allowing platelet adhesion
Platelets swell and change shape to cover a larger area
What is secondary Haemostasis
The clotting cascade
Involving the intrinsic and the extrinsic pathways
What is the extrinsic pathway
Pathway that would occur from external damage
What is the intrinsic pathway
The pathway hat would occur when would have the exposure of collagen
What is Von Willebrand factor
Stimulates platelet adhesion
Platelets would expose the GPBl receptor (glycoprotein binding 1)
Would allow then to stick together
(Comes from the subendothelium space)
What would happen in the intrinsic pathway
Factor 12 - activates factor 11- activates factor 9 - would bind with calcium and factor 8 and would then stimulate factor 10 (goes to the common pathway)
What happens in the extrinsic pathway
Tissue factor (TF) would activate factor 7
Would activate factor 10
Would go to the common pathway
What happens in the common pathway
Factor 10 would bind to factor 5 and Calcium
This would then form a promthormobinase complex
This would then convert prothrombin to thrombin (factor 2)
Thrombin would then convert fibrinogen to fibrin (factor 1)
What occurs in fibrolysis
Plasminogen goes to plasmin (via tissue plasminogen activator)
Plasmin would then cleave the insoluble fibrin to a soluble product
(Release of d-dimer as a by product)
What is d-dimer
Degradation protein of fibrolysis
What is Von willebrand disease
Autosomal dominant
Deficiency of Von willebrands factor (from the sub endothelium space)
There would be no binding of the platelets
What factors would he deficient in the haemophilias
A- 8 (x linked recessive)
B- 9 (x linked recessive)
C- 11 (autosomal recessive)
What are the dense granules
ADP (would stimulate the GDllb/lla)
Calcium
Serotonin
What are the alpha granules
Fibrinogen
Von willebrands factor
Platelet factor 3
Platelet activating factor (PAF)
What else does thrombin do
Activates factor 13 (a stabilising factor)
Cleaves fibrinogen to fibrin
What are the typical symptoms of the bleeding disorders
Excessive bleeding
Excessive nose bleeds
Bleeding in joints
Easy bruising
What other things can lead to aquired bleeding disorders
Liver disease (produces the tPA)
Vitamin k (deficiency in factors 2, 7, 9 and 10)
Warfarin (vitamin k antagonists - anticoagulant)
What occurs in disseminated intravascular coagulapathy
Over-coagulation and excessive bleeding
Occurs in sepsis, cancers, pregnancy
What are the forms of lab testing
D-dimer
Blood time
Platelet count
Prothrombin time (vitamin K factors 2,7,9,10)
Acquired partial thromboplastin time (factors 12,11,9,8)
What factors does the prothrombin test test for
Vitamin k dependent factors 2, 7, 9, 10
What factors does activated partial thromboplastin time test for
Factors from the intrinsic pathway
12, 11, 9, 8
Would be for the haeomphillacs
What does d-dimer test for
Would be a degradation product of fibrolysis
Correct function detected
What is the normal platelet count
150/400
