What is the proper name for the chemical released by damaged blood vessels?

What is the proper name for the chemical released by damaged blood vessels?

• A. Platelet-derived growth factor
• B. Hemoglobin
• C. Fibrinogen
• D. Von Willebrand Factor (VWF)

Answer: (D)

When a blood vessel is damaged, the first step of stopping bleeding relies on the endothelium releasing von Willebrand factor. This large protein acts as a bridge between exposed subendothelial collagen and platelets by binding to the platelet receptor GPIb, allowing platelets to adhere at the injury site and start forming a plug. This rapid release is essential for initiating primary hemostasis and helps recruit more platelets to seal the break. Von Willebrand factor also protects factor VIII in circulation, supporting stability of subsequent clot formation. Platelet-derived growth factor, released by activated platelets, mainly promotes tissue repair rather than immediate adhesion at the injury. Hemoglobin is the oxygen-carrying protein inside red blood cells and isn’t a signaling molecule released by vessel damage. Fibrinogen is a plasma protein that becomes fibrin during clot formation later in the cascade, but it isn’t the chemical released specifically by damaged vessels to initiate adhesion.

When a blood vessel is damaged, the first step of stopping bleeding relies on the endothelium releasing von Willebrand factor. This large protein acts as a bridge between exposed subendothelial collagen and platelets by binding to the platelet receptor GPIb, allowing platelets to adhere at the injury site and start forming a plug. This rapid release is essential for initiating primary hemostasis and helps recruit more platelets to seal the break. Von Willebrand factor also protects factor VIII in circulation, supporting stability of subsequent clot formation.

Platelet-derived growth factor, released by activated platelets, mainly promotes tissue repair rather than immediate adhesion at the injury. Hemoglobin is the oxygen-carrying protein inside red blood cells and isn’t a signaling molecule released by vessel damage. Fibrinogen is a plasma protein that becomes fibrin during clot formation later in the cascade, but it isn’t the chemical released specifically by damaged vessels to initiate adhesion.