Question

Which of the following factors play a major role in the initiation of thrombus formation ?

• A. Vasoconstriction
• B. Coagulation cascade activation
• C. Platelets activation
• D. Endothelial injury

Answer 1

The Correct Option is D

Thrombus formation, also known as blood clotting, is a complex process crucial for stopping bleeding when a blood vessel is injured. One of the primary factors initiating thrombus formation is endothelial injury. When the endothelium, the inner lining of blood vessels, is damaged, it exposes underlying tissues, triggering a sequence of events:

1. Endothelial Injury: The process begins with the disruption of the endothelial layer, revealing the subendothelial matrix, which is rich in collagen and tissue factor.
2. Platelets Activation: Upon exposure to collagen, platelets adhere to the injury site, undergo activation, release granules, and recruit additional platelets to form a platelet plug.
3. Coagulation Cascade Activation: Tissue factor exposed by the injury activates a series of enzymatic reactions known as the coagulation cascade, ultimately leading to the formation of fibrin strands that stabilize the platelet plug.
4. Vasoconstriction: Though not a primary initiator, vasoconstriction aids in reducing blood flow to the affected area, facilitating the actions of platelets and coagulation factors.

Thus, while all these factors contribute to the process of thrombus formation, endothelial injury is the initial trigger that sets the entire mechanism into motion.