ANATOMY

Detailed explanation-1: -The mast cell secretes histamine by exocytosis when it is stimulated immunologically by binding of a specific antigen to IgE molecules in the cell membrane. Histamine secretion may also be induced by non-immunological stimulators such as polymeric amines, neuropeptides and calcium-ionophores.

Detailed explanation-2: -Mast cells and basophils represent the most relevant source of histamine in the immune system.

Detailed explanation-3: -They secrete serotonin, heparin and histamine when they are activated in the presence of the toxic substance or pathogen.

Detailed explanation-4: -Mast cells They’re an important part of the immune system and help fight infection. When mast cells detect a substance that triggers an allergic reaction (an allergen), they release histamine and other chemicals into the bloodstream. Histamine makes the blood vessels expand and the surrounding skin itchy and swollen.