GENERAL HISTOLOGY

Detailed explanation-1: -[12] Secretin increases bicarbonate secretion from duodenal Brunner’s gland as well; this mechanism buffers the acidity from chyme and reduces secretion of acid by parietal cells.

Detailed explanation-2: -The duodenum is a short section of the small intestine located between the stomach and the rest of the small intestine. The duodenum also produces the hormone secretin to stimulate the pancreatic secretion of large amounts of sodium bicarbonate, which then raises pH of the chyme to 7.

Detailed explanation-3: -Brunner’s glands are located in the submucosa of the duodenum. They secrete an alkaline fluid containing mucin, which protects the mucosa from the acidic stomach contents entering the duodenum.

Detailed explanation-4: -Brunner’s glands are unique to mammalian species and in eutherians are confined primarily to the submucosa of the proximal duodenum. In the majority of species examined, they begin at the gastrointestinal junction and extend for variable distances distally in the wall of the proximal small intestine.

Detailed explanation-5: -With a pH of around 2, chyme emerging from the stomach is very acidic. To raise its pH, the duodenum secretes a hormone, cholecystokinin (CCK), which causes the gall bladder to contract, releasing alkaline bile into the duodenum.