Structural Organisation in AnimalsHard
Question
Which of the following substances, if introduced into the lood stream, would cause coagulation of blood at the site of its introduction ?
Options
A.Prothrombin
B.Fibrinogen
C.Thromboplastin
D.Heparin
Solution
Lipoproteinaceous thromboplastin is released by the injured tissue. This reacts with Ca2+ iong persent in bollod and a proteinaceoue enzyme called prothrombinase. Later in the presence of Ca2+ inactivates heparin (anticoagulant) and catalyses prothrombin (inactive plasma protein) into an active thrombin protein. Thrombin acts as an enzyme and catalyses fibinogen (a soluble plasma protein) into an insoluble fibre like polymer, fibrin, These fibres form a dense natwork upon the wound and trap blood corpuscles (WBCs, RBCs and platelets) and thus form a clot. This clot seals the wound and stop bleeding. In blood vessels, thromboplastin do not release due to which blood does not clot. But external thromboplastin to blood will cause blood clotting at the site of its introduction due to formation of prothrombinase.
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