Blood Clotting Process: Coagulation Cascade

Blood Clotting Process

Coagulation Cascade

• Series of chemical reactions that ultimately lead to the formation of a blood clot
• Divided into two pathways:
  • Intrinsic pathway: triggered by damage to blood vessels, involves contact activation of factor XII
  • Extrinsic pathway: triggered by tissue damage, involves release of tissue factor
• Both pathways converge to form a common pathway, leading to the formation of thrombin
• Thrombin converts fibrinogen to fibrin, which forms the clot

Platelet Activation

• Platelet activation: platelets become activated in response to vascular injury
• Platelet aggregation: activated platelets aggregate to form a platelet plug
• Release of granules: activated platelets release granules containing:
  • Adenosine diphosphate (ADP)
  • Thromboxane A2
  • Serotonin
• These granules attract more platelets, amplifying the clotting response

Clot Retraction

• Clot retraction: the process by which the blood clot is tightened and stabilized
• Clot contraction: platelets contract, pulling the fibrin meshwork together
• Clot stabilization: the clot becomes more stable, allowing for wound healing to occur

Thrombus Formation

• Thrombus: a blood clot that forms within a blood vessel
• Arterial thrombi: form in arteries, can lead to myocardial infarction or stroke
• Venous thrombi: form in veins, can lead to pulmonary embolism

Fibrin Formation

• Fibrinogen: a glycoprotein produced by the liver
• Thrombin: converts fibrinogen to fibrin
• Fibrin polymerization: fibrin molecules polymerize to form a meshwork, trapping platelets and blood cells
• Clot formation: the fibrin meshwork forms the basis of the blood clot

Blood Clotting Process

Coagulation Cascade

• A series of chemical reactions that lead to blood clot formation
• Divided into two pathways: intrinsic (triggered by blood vessel damage) and extrinsic (triggered by tissue damage)
• Both pathways converge to form a common pathway, leading to thrombin formation
• Thrombin converts fibrinogen to fibrin, forming the clot

Platelet Activation

• Platelets become activated in response to vascular injury
• Activated platelets aggregate to form a platelet plug
• Release granules containing ADP, thromboxane A2, and serotonin, attracting more platelets and amplifying the clotting response

Clot Retraction

• The process of clot tightening and stabilization
• Platelets contract, pulling the fibrin meshwork together
• The clot becomes more stable, allowing for wound healing

Thrombus Formation

• A blood clot that forms within a blood vessel
• Arterial thrombi form in arteries, potentially leading to myocardial infarction or stroke
• Venous thrombi form in veins, potentially leading to pulmonary embolism

Fibrin Formation

• Fibrinogen, a glycoprotein produced by the liver, is converted to fibrin by thrombin
• Fibrin molecules polymerize to form a meshwork, trapping platelets and blood cells
• The fibrin meshwork forms the basis of the blood clot