Definition of coagulation

Photonics Dictionary

coagulation: Coagulation refers to the process of transforming a liquid, particularly blood or a solution containing dispersed particles, into a solid or semi-solid state. This term is most commonly associated with blood clotting but can also apply to other processes in chemistry and biology.

In the context of blood, coagulation is the complex process by which blood forms clots to stop bleeding. It involves a cascade of events that include:

Vasoconstriction: The blood vessels constrict to reduce blood flow.

Platelet plug formation: Platelets adhere to the site of injury and to each other, forming a temporary platelet plug.

Activation of clotting factors: A series of proteins (clotting factors) in the blood plasma are activated in a stepwise manner. This process, known as the coagulation cascade, involves intrinsic and extrinsic pathways that converge on the activation of Factor X.

Formation of fibrin mesh: The enzyme thrombin converts fibrinogen into fibrin, which forms a mesh that stabilizes the platelet plug into a durable clot.

Clot retraction and repair: The clot contracts to pull the edges of the wound together, and tissue repair begins.

This process is crucial for preventing excessive bleeding when blood vessels are injured.

In chemistry, coagulation refers to the process by which dispersed particles in a liquid aggregate to form a floc or a precipitate. This can occur through:

Addition of coagulants: Chemicals (coagulants) are added to a suspension to neutralize charges on particles, causing them to clump together.

Flocculation: Aggregated particles form larger clusters (flocs) that can be separated from the liquid by sedimentation, filtration, or centrifugation.

This principle is widely used in water treatment and in the purification of various industrial processes.

In industrial processes, coagulation is used in manufacturing and materials processing. For example, in rubber coagulation, where latex is coagulated to form solid rubber by adding acids or other coagulants.

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