BLOOD COAGULATION -

DEFINITION -

The property of blood to change from fluid to gel state within a few minutes of its coming in contact with air is called blood coagulation or blood clotting or haemostasis.

PERIOD -

The clot begins to develops in 15 to 20 seconds but is fully formed within 3 to 6 minutes in a normal person.

FACTORS INVOLVED -

According to internation commission on blood coagulation (1954), thirteen coagulation factors are involved -

I.        Fibrinogen (synthesized in liver)

II.       Prothrombin (synthesized in liver)

III.      Thromboplastin (a lipoproteinous enzyme released from damaged tissues blood plateles in mammals).

IV.      Calcium ion (activates thromboplastin).

V.       Labile factor or proaccelerin (synthesized in liver).

VI.      Accelerin (Hypothetical factor, the term is no longer used).

VII.     Stable factor or proconvertin (synthesized in liver).

VIII.    Antihaemophilic factor (AHF - synthesized in liver. Its deficiency causes haemophilia-A).

IX.      Christmas factor or plasma thromboplastin component (PTC-synthesized in liver). Its deficiency causes haemophilia-B or christmas disease.

X.       Stuart Power factor (synthesized in liver)

XI.      Plasma thromboplastin antecedent (PTA-synthesized in liver). Its deficiency causes haemophilia-C.

XII.     Hageman or surface factor (activated when comes in contact with skin surface).

XIII.    Fibrin - Stabilizing factor (FSF)