The Fate of Blood Clots

After a clot has formed, spinous pseudopods of the platelets adhere to strands of fibrin and contract. This pulls on the fibrin threads and draws the edges of the broken vessel together, like a drawstring closing a purse.

Saladin: Anatomy & I 18. The Circulatory System: I Text I © The McGraw-Hill

Physiology: The Unity of Blood Companies, 2003 Form and Function, Third Edition

Mechanism Dissolving Blood Clots

Figure 18.23 The Mechanism for Dissolving Blood Clots.

Prekallikrein is converted to kallikrein. Kallikrein is an enzyme that catalyzes the formation of plasmin. Plasmin is an enzyme that dissolves the blood clot.

Figure 18.23 The Mechanism for Dissolving Blood Clots.

Prekallikrein is converted to kallikrein. Kallikrein is an enzyme that catalyzes the formation of plasmin. Plasmin is an enzyme that dissolves the blood clot.

• Dilution. Small amounts of thrombin form spontaneously in the plasma, but at normal rates of blood flow the thrombin is diluted so quickly that a clot has little chance to form. If flow decreases, however, enough thrombin can accumulate to cause clotting. This can happen in circulatory shock, for example, when output from the heart is diminished and circulation slows down.

• Anticoagulants. Thrombin formation is suppressed by anticoagulants that are present in the plasma. Antithrombin, secreted by the liver, deactivates thrombin before it can act on fibrinogen. Heparin, secreted by basophils and mast cells, interferes with the formation of prothrombin activator, blocks the action of thrombin on fibrinogen, and promotes the action of antithrombin. Heparin is given by injection to patients with abnormal clotting tendencies.

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  • raffaella
    What are the fates of blood clot?
    3 years ago
  • Kerstin Adler
    What are the fate of blood clot?
    3 years ago

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