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When the stomach pH decreases (becomes more acidic), the ECLs stop releasing histamine. G cells – They secrete gastrin hormone. Gastrin stimulates the gastric glands to release gastric acid. These cells are mostly found in pyloric glands in the pyloric antrum; some are found in the duodenum and other tissues. The gastric pits of these glands ...
The stomach is a distensible organ and can normally expand to hold about one litre of food. [22] This expansion is enabled by a series of gastric folds in the inner walls of the stomach. The stomach of a newborn baby will only be able to expand to retain about 30 ml.
A canaliculus is an adaptation found on gastric parietal cells. It is a deep infolding, or little channel, which serves to increase the surface area, e.g. for secretion. The parietal cell membrane is dynamic; the numbers of canaliculi rise and fall according to secretory n
This structure consists of connective tissue covered by a simple squamous epithelium, called the mesothelium, which reduces frictional forces during digestive movements. The intraperitoneal regions include most of the stomach , first part of the duodenum , all of the small intestine , caecum and appendix , transverse colon , sigmoid colon and ...
The secretion is a complex and relatively energetically expensive process. Parietal cells contain an extensive secretory network (called canaliculi) from which the hydrochloric acid is secreted into the lumen of the stomach. The pH of gastric acid is 1.5 to 3.5 in the human stomach lumen, a level maintained by the proton pump H + /K + ATPase. [1]
In humans, it is about one mm thick, and its surface is smooth, soft, and velvety. It consists of simple secretory columnar epithelium , an underlying supportive layer of loose connective tissue called the lamina propria , and the muscularis mucosae , a thin layer of muscle that separates the mucosa from the underlying submucosa.
H + is pumped into the stomach by exchanging it with K +. This process also requires ATP as a source of energy; however, Cl − then follows the positive charge in the H + through an open apical channel protein. HCO 3 − secretion occurs to neutralize the acid secretions that make their way into the duodenum of the small intestine.
The stomach is involved in the gastric phase of digestion, following the cephalic phase in which the sight and smell of food and the act of chewing are stimuli. In the stomach a chemical breakdown of food takes place by means of secreted digestive enzymes and gastric acid. The stomach is located between the esophagus and the small intestine.