CPT Haem Revision Flashcards
What do platelets release on activation?
ADP TXA Serotonin Calcium Change shape = express GpIIb/IIIa
5-HT function
Platelet chemotaxis
Release by active platlets
TXA/ADP function
Activates other platelets
Platelet diameter
1-4 micrometer
Platelet lifespan
8-14 days
Primary Haemostasis
Injury to vessel wall Vasoconstriction Exposed collagen VWF binds to collagen VWF binds to platelets via Gp1b Platelet activation = express GpIIb/IIIa Fibrinogen binds to these receptors Further platelets bind to fibrinogen
Bernard Soulier Syndrome
Lack of Gp1b
Glanzmanns syndrome
Lack of GpIIb/IIIa
Treatment for Bernard Soulier and Glanzmanns
Platelets or novoseven (recombinant factor VIIa) or transxamic acid
VWD types
Mild = mild to moderate deficiency Moderate = present but defective Severe = absent
VWD Inheritance
Autosomal inheritance
VWD Treatment
DDAVP if mild
Tranexamic acid
VWF containing concentrate
Intrinsic Pathway
12->12a converts 11->11a converts 9->9a.
9-> 9a requires XIa and calcium
9a converts 10-> 10a with calcium and 8
Extrinsic Pathway
TF(3) converts VII -> VIIa
VIIa converts 10-> 10a
Function of 10a
With 5 and calcium converts prothrombin into thrombin
Thrombin converts fibrinogen into fibrin
Factor 13a helps fibrin form stable clot
13a comes from thrombin producing 13
APTT
Intrinsic = 12,11,9 with 8 = 10