IMMUNOLOGY

Detailed explanation-1: -One of the best-known chemical mediators released from cells during inflammation is histamine, which triggers vasodilation and increases vascular 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: -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.

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: -Mast cells release histamine as well as other vasoactive molecules, which cause urticaria (hives).

Detailed explanation-6: -The released chemical mediators include (1) vasoactive amines such as histamine and serotonin, (2) peptide (e.g., bradykinin), and (3) eicosanoids (e.g., thromboxanes, leukotrienes, and prostaglandins).

Detailed explanation-7: -The inflammatory response increases the amount of blood flow to the site of injury to get more nutrients and white blood cells to an area in need. To increase blood flow to the area, the blood vessels get wider (dilate).