Each day, about 9 liters of fluid enters the duodenum. Most chemical digestion takes place in the duodenum by chemicals secreted by the liver, pancreas and small intestine. The other two sections of the small intestine, the jejunum and the ileum, absorb food molecules by way of the villi directly into the blood stream.
Histamine is synthesised in the brain in the hypothalamus, in a specific area known as the tuberomamillary nucleus (TMN), where it acts as a signalling messenger (or neurotransmitter). The hypothalamus is the area of the brain that overseas the metabolic processes of the body found in the central nervous system.
It is thought to be a major mediator of the acute. inflammatory response, although histamine H1. antagonists have little effect on acute inflammation. [5]. Histamine playes a pivotal role in many types of. allergic and inflammatory processes, including both. acute and delayed hypersensitivity reactions [5]. The source of histamine in such cases is tissue mast cells. The magnitude of such problems depends on the route of exposure (local versus systemic), sites of exposure (e.g. inhaled versus cutaneous), the dose of allergen, and the degree of previous sensitization to the allergen.