What occurs during platelet plug formation?

• A. Fibrin mesh forms a stable clot.
• B. Red blood cells accumulate.
• C. White blood cells migrate.
• D. Platelets adhere to damaged site and to each other to form a temporary platelet plug.

Answer: (D)

During platelet plug formation, the body rapidly seals a small vessel injury by platelets sticking to the damaged site and to each other, creating a temporary plug. When the vessel is breached, exposed collagen and von Willebrand factor at the injury promote platelet adhesion. Platelets then become activated, changing shape and releasing granules that recruit more platelets (such as ADP and thromboxane A2). They aggregate through fibrinogen linking of receptors (GPIIb/IIIa) on adjacent platelets, forming a loose, temporary platelet plug that helps stop the bleeding quickly. This step comes before the formation of a stable fibrin clot, which requires the coagulation cascade to produce a fibrin mesh. Red blood cells may get trapped in the plug, and white blood cells may migrate later as part of inflammation, but the defining action in platelet plug formation is platelets adhering to the injury and to each other to form the initial seal.