of, relating to, or of the nature of preference: preferential policies. 2. showing or giving preference: a preferential hiring system. 3. receiving or enjoying preference, as a country in trade relations; favored. Origin of preferential.
Histamine dilates post-capillary venules, activates the endothelium, and increases blood vessel permeability. This leads to local edema (swelling), warmth, redness, and the attraction of other inflammatory cells to the site of release. It also depolarizes nerve endings (leading to itching or pain).
As previously mentioned, histamine is a chemical stored within our body. It is produced by cells known as mast cells. Histamine is a protein molecule with the chemical formula C5H9N3. It serves as an important part of our body's immune response.When we come into contact with an allergen, such as pollen or animal dander, histamine is released by the body to the site of contact.hen the histamine arrives at the site of irritation, it causes several important effects. One is the dilating, or widening, of small blood vessels in that area. This is known as an inflammatory response, or swelling. Swelling increases the flow of blood to the area.