Haemostasis fundamentals Flashcards
What is haemostasis?
balance of procoagulant and anticoagulant activity
Name two anticoagulants and how they work
EDTA and Sodium citrate
Both bind to calcium
What is primary haemostasis?
Interaction from platelets
Describes the first phase of coagulation
What is secondary haemostasis?
Clotting cascade element - fibrin formation
Second phase of coagulation
What is fibrinolysis?
Removing the blood clot
Final phase of coagulation
What is haemophilia?
Clotting factor deficiency
Can’t generate enough fibrin
What are platelets made from?
The cytoplasm form megakaryocytes
What is platelet production driven by?
The hormone Thrombopoietin
What does a platelet cell membrane consist of?
Glycoproteins which are receptors
What are some key platelet functions?
Interact with VWF and other platelets
Deliver further haemostatic factors at the injured site
Provide a negatively charged surface
Localise thrombus repair
Promotes vasoconstriction
What are the vitamin K dependent factors?
Factor II (2) - prothrombin
Factor VII (7)
Factor IX (9)
Factor X (10)
Protein C
Protein S
What are the main functions of thrombin?
Back activation of clotting cascade (VIII & V)
In vivo activator of XI
Activator of fibrinogen
Activator of XIII - stabilises thrombin
Activation of platelets
Where is vitamin K derived from?
Diet and intestinal bacteria
What temperature must blood coagulation tests be performed at?
37 degrees Celsius
What do platelet alpha granules contain?
Factors V, FVIII
vWF
Fibrinogen
