When the blood is shed or drawn from a vein
, it looses its fluidity in a few minutes and sets into semi solid jelly like
mass . The phenomenon is called ‘coagulation ‘ or clotting of blood . In a test
tube , if the blood is collected , it is observed that after coagulation . The
clot refracts to a smaller volume and serum
will separate . The serum will smaller not clot any more . In the formation of
clot , R.B.C and W.B.C have no role but platelets take some important part in
the process of coagulation . Under ultra microscope if the process of
coagulation is observed , it is seen that there will be formation of minute
granules , often near a clump of disintegrating
platelets . These minute granules will unite to form needles . These
needles will again unite and form long thread and form net-work . In the
net-work , R.B.C and W.B.C will be
enlarged and the serum separate out .
Factors responsible for Blood coagulation
…..
1.
Factor I -
Fibrinogen
2.
Factor II - Prothrombin
3.
Factor III - Thromboplastin
4.
Factor IV - Calcium
5.
Factor V - Labile
factor ( pro-acetarin , plasma ac-globin )
6.
Factor VI - Accelerin
7.
Factor VII - Proconvertin
8.
Factor VIII - Anti-haemophilic
globulin ( AHG )
9.
factor IX - Plasma thromboplastin component
10. Factor X - Stuart power factor
11. Factor XI - Plasma thromboplastin antecedent (
PTA )
12. Factor XII - Hageman factor ( HF )
13. FactorXIII - Fibrin stabilizing factor
