ANATOMY

Detailed explanation-1: -Injured tissue mast cells release histamine, causing the surrounding blood vessels to dilate and increase in permeability.

Detailed explanation-2: -During acute inflammatory responses, leukocyte-derived mediators such histamine and bradykinin will cause arteriolar dilation thereby increasing blood flow leading to rubor.

Detailed explanation-3: -Chemical mediators of inflammation One of the best-known chemical mediators released from cells during inflammation is histamine, which triggers vasodilation and increases vascular permeability.

Detailed explanation-4: -Histamine is a major preformed mediator released by mast cells and it strongly increases vascular permeability. This increase in vascular permeability is responsible for several features of acute allergic reactions including edema, urticaria, and anaphylactic shock in serious cases.

Detailed explanation-5: -Histamines are responsible for dilating blood vessels and increasing their permeability in inflammation. Heparin inhibits blood clotting, and also promotes the movement of leukocytes into an area of infection.