Question

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Usually the wound stop bleeding within 3-7 minutes to prevent
loss of blood. Describe the mechanism of blood clotting.
Carries 3 marks
Class 11 CBSE

Answer 1

Hemostasis occurs when blood is present outside of the body or blood vessels. It is the innate response for the body to stop bleeding and loss of blood. During hemostasis three steps occur in a rapid sequence. Vascular spasm is the first response as the blood vessels constrict to allow less blood to be lost.

and iam als in class 11th PCB CBSE

Answer 2

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Blood Clotting : Blood clotting helps for the excessive loss of blood from an injury caused to the body. It is initiated by platelets. Thromboplastin is a lipoprotein plays a major role in blood clotting.

Formation of Clot occurs in three steps :

1). Thromboplastin helps in the formation of prothrombinase enzyme. This enzyme inactivates heparin and it also converts the inactive prothrombin into active thrombin. Calcium ions helps for these changes.

2). Thrombin acts as a proteolytic enzyme to separate two peptides from the soluble fibrinogen molecule to form insoluble fibrin.

3). The fibrin polymerizes to form long, sticky fibres. The fibrin threads form a fine network over the wound and tap blood cells to form a crust – the CLOT.

Note : : Clot is formed in about 2 – 8 minutes and seals the wound and stop bleeding.