Blood normally flows as a fluid, but an injury can trigger a controlled process that stops bleeding. This lesson explains how platelets and clotting factors work together, how fibrin stabilizes a clot, and how the body limits and removes clots. These foundations also help explain why abnormal clot formation can lead to serious disease.
Hemostasis is the body's ability to stop bleeding after blood vessel damage. It has two closely linked components.
All flashcards
What is primary hemostasis?
The platelet-based response to vessel injury in which platelets adhere, activate, and aggregate to form a platelet plug.
What is secondary hemostasis?
Activation of clotting factors that generates fibrin, strengthening the platelet plug into a more stable clot.
How do the intrinsic and extrinsic pathways connect to the common pathway?
Both pathways activate factor X to factor Xa, which begins the common pathway.
What do thrombin and fibrin do in clot formation?
Thrombin converts fibrinogen into fibrin and also reinforces coagulation by activating factors such as V and VIII. Fibrin forms strands that stabilize the clot.
What is Factor V Leiden?
An inherited mutation that makes factor V less susceptible to inactivation and increases the person's risk of thrombosis.
Quiz questions
What is the main event in primary hemostasis?Answer: Platelets adhere and aggregate at the injury site to form a platelet plug.
Which factor complex helps the extrinsic pathway activate factor X?Answer: Tissue factor working with factor VIIa.
How do proteins C and S limit coagulation?Answer: They work together to inhibit activated factors Va and VIIIa.
What is the likely effect of reduced antithrombin activity?Answer: Inhibition of thrombin and factor Xa is reduced, which can increase clotting tendency.
How does tissue plasminogen activator contribute to clot regulation?Answer: It promotes conversion of plasminogen to plasmin, which degrades fibrin.
Based on Pharmacology for Nurses by Tina Barbour-Taylor, Leah Mueller (Sabato), Donna Paris, Dorie Weaver (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.