Question

* are widely present throughout the body in latent forms. These mediators are found in concentrated amounts as granules in near endothelial cells (tissue). Injury to tissue activates the mast cells that will then decal and release cell mediators. Histamine dilates arterioles and increases permeability of venules _release is a key step in the synthesis of prostaglandins and leukotrienes. Arachidonic Acid

Answer 1

Histamine is found in the granules of mast cells and basophils. Also found in platelets

1. Physical stimulation such as trauma or cold

2. IgE

3. C3a and C5a (the anaphylatoxins

4. Histamine releasing factors from PMNs, monocytes, and platelets

5. IL-1

The degranulation is mediated by a cAMP second messenger system which causes the histamine release.

PAF (platelet activating factor), contact with collagen, thrombin, AFP, and antibody-antigen interactions.

Fill ups :-

1. Basophils

2. Mast cells

3. Degranulate

4. Archidonic acid