GENERAL HISTOLOGY

Detailed explanation-1: -Food passing from your stomach into the first part of your small intestine (duodenum) triggers the next stage of the digestive process. When cells in the mucosal lining of your duodenum (called I-cells) detect the presence of proteins and fats to digest, they trigger cholecystokinin to release into circulation.

Detailed explanation-2: -What is cholecystokinin? Cholecystokinin is produced by I-cells in the lining of the duodenum and is also released by some neurons in the brain. It acts on two types of receptors found throughout the gut and central nervous system.

Detailed explanation-3: -CCK is produced by two separate cell types: endocrine cells of the small intestine and various neurons in the gastrointestinal tract and central nervous system. Accordingly, CCK can function as either a hormone or a neuropeptide.

Detailed explanation-4: -The small intestines, namely the duodenum and jejunum handle secretion of CCK, secretin, GIP, and motilin.

Detailed explanation-5: -secretin, a digestive hormone secreted by the wall of the upper part of the small intestine (the duodenum) that regulates gastric acid secretion and pH levels in the duodenum.