Intrinsic Pathway

Definition

The intrinsic pathway, also known as the contact activation pathway, is one of the two main pathways of the blood coagulation cascade. It is initiated by the activation of factor XII (Hageman factor) and leads to the formation of a fibrin clot, which helps to stop bleeding and promote healing.

5 Must Know Facts For Your Next Test

1. The intrinsic pathway is triggered by the activation of factor XII, which then activates factor XI, leading to the activation of factor IX and the subsequent activation of factor X.
2. The intrinsic pathway is responsible for the majority of the clotting factors involved in the coagulation cascade, including factors VIII, IX, XI, and XII.
3. The intrinsic pathway is slower to activate than the extrinsic pathway, which is triggered by the exposure of tissue factor to the bloodstream.
4. The intrinsic pathway is important for the maintenance and regulation of the coagulation cascade, as it helps to ensure that clot formation is sustained and controlled.
5. Deficiencies or abnormalities in the intrinsic pathway can lead to bleeding disorders, such as hemophilia A (factor VIII deficiency) and hemophilia B (factor IX deficiency).

Review Questions

• Explain the role of the intrinsic pathway in the coagulation cascade.
  • The intrinsic pathway is one of the two main pathways of the coagulation cascade, which is responsible for the formation of a fibrin clot to stop bleeding and promote healing. The intrinsic pathway is initiated by the activation of factor XII (Hageman factor), which then activates a series of other coagulation factors, leading to the activation of factor X and the eventual formation of a fibrin clot. The intrinsic pathway is important for the maintenance and regulation of the coagulation cascade, as it helps to ensure that clot formation is sustained and controlled.
• Describe the relationship between the intrinsic pathway and the extrinsic pathway in the coagulation cascade.
  • The intrinsic pathway and the extrinsic pathway are the two main pathways of the coagulation cascade, and they work together to promote the formation of a fibrin clot. The extrinsic pathway is triggered by the exposure of tissue factor to the bloodstream, which activates factor VII and leads to the activation of factor X. The intrinsic pathway, on the other hand, is initiated by the activation of factor XII and leads to the activation of factor IX and factor X. While the extrinsic pathway is faster to activate, the intrinsic pathway is responsible for the majority of the clotting factors involved in the coagulation cascade and helps to ensure that clot formation is sustained and controlled.
• Analyze the clinical implications of deficiencies or abnormalities in the intrinsic pathway.
  • Deficiencies or abnormalities in the intrinsic pathway can lead to bleeding disorders, such as hemophilia A (factor VIII deficiency) and hemophilia B (factor IX deficiency). These disorders are characterized by prolonged bleeding and an increased risk of spontaneous bleeding episodes, as the coagulation cascade is unable to function properly without the necessary clotting factors. Individuals with these disorders may require regular infusions of the missing clotting factors or other treatments to manage their condition and prevent life-threatening bleeding events. Understanding the role of the intrinsic pathway in the coagulation cascade is crucial for the diagnosis, management, and treatment of these types of bleeding disorders.

Related terms

Coagulation Cascade: The coagulation cascade is a series of enzymatic reactions that lead to the formation of a fibrin clot, which helps to stop bleeding.

Factor XII (Hageman Factor): Factor XII is a serine protease that initiates the intrinsic pathway of the coagulation cascade when it is activated by contact with a foreign surface, such as damaged blood vessels or exposed collagen.

Fibrin Clot: A fibrin clot is a mesh-like network of fibrin proteins that forms at the site of a wound or injury, trapping blood cells and platelets to help stop bleeding and promote healing.