Blodplugg

Blodplugg, or blood plug, is a term used to describe the initial, temporary seal that forms at a site of vascular injury as part of hemostasis. It is primarily composed of aggregated platelets and adherent proteins, and it serves to rapidly reduce blood loss while the coagulation cascade works to create a more stable thrombus. The concept covers the early, platelet-driven phase of clotting, before and during reinforcement by fibrin.

Formation of the blodplugg begins with vascular injury, which causes vasoconstriction and exposure of subendothelial components such as collagen and von Willebrand factor. Platelets adhere to the injured area via receptors that interact with these factors, become activated, and release granule contents (including ADP, serotonin, and thromboxane A2). Activated platelets change shape, express surface receptors (notably GPIIb/IIIa), and recruit additional platelets, leading to rapid platelet aggregation and plug formation within seconds.

Stabilization occurs when the coagulation cascade is activated, converting fibrinogen to fibrin. The fibrin network interlaces with the platelet plug, producing a more durable thrombus that seals the injury sites and provides a scaffold for tissue repair. Over time, regulatory mechanisms balance procoagulant and anticoagulant forces to prevent excessive clotting.

Clinical relevance varies with context: insufficient blodplugg formation can lead to excessive bleeding, while overactive plug formation can contribute to thrombosis and vascular occlusion. Disorders of platelet number or function, or drugs that impair platelet activity, can affect plug formation. Understanding the blodplugg is central to the broader study of hemostasis and thrombosis.