Simulation · Biology · Class 11
The clotting cascade
From the lesson Coagulation of blood in Body Fluids and Circulation. Change the values and watch what happens.
The clotting cascadeBiology · Class 11
The idea behind it
NCERT §15.1.4
- Blood clots in response to injury or trauma; this stops excessive loss of blood.
- The dark reddish-brown scum over a cut is a clot (coagulum): a mesh of threads called fibrin in which dead and damaged formed elements are trapped.
- Fibrin is made from inactive fibrinogen in plasma by the enzyme thrombin.
- Thrombin itself is made from another inactive plasma substance, prothrombin. This step needs an enzyme complex, thrombokinase.
- Thrombokinase forms through a cascade: a chain of linked enzyme reactions involving several factors present in plasma in an inactive state.
- Injury stimulates platelets to release factors that set the cascade going; factors released by damaged tissue at the site can also start it.
- Calcium ions play a very important role in clotting.