gastrointestinal hormones is the chemical produced and secreted by the lining of the stomach.
gastrointestinal hormones is the chemical produced and secreted by the lining of the stomach.
the chemical produced and secreted by the lining of the stomach is?
gastrointestinal hormones
these enzymes are secreted in a fluid rich in bicarbonate. bicarbonate helps maintain an alkaline ph for the fluid, a ph in which most of the enzymes act most efficiently, and also helps to neutralise the stomach acids that enter the duodenum. secretion is influenced by hormones including secretin, cholecystokinin, and vip, as well as acetylcholine stimulation from the vagus nerve. secretin is released from the s cells which form part of the lining of the duodenum in response to stimulation by gastric acid. along with vip, it increases the secretion of enzymes and bicarbonate. cholecystokinin is released from ito cells of the lining of the duodenum and jejunum mostly in response to long chain fatty acids, and increases the effects of secretin. at a cellular level, bicarbonate is secreted from the acinar cells through a sodium and bicarbonate cotransporter that acts because of membrane depolarisation caused by the cystic fibrosis transmembrane conductance regulator. secretin and vip act to increase the opening of the cystic fibrosis transmembrane conductance regulator, which leads to more membrane depolarisation and more secretion of bicarbonate.
pancreas
the second vital secretion of the gi tract is that of digestive enzymes that are secreted in the mouth, stomach and intestines. some of these enzymes are secreted by accessory digestive organs, while others are secreted by the epithelial cells of the stomach and intestine. while some of these enzymes remain embedded in the wall of the gi tract, others are secreted in an inactive proenzyme form. when these proenzymes reach the lumen of the tract, a factor specific to a particular proenzyme will activate it. a prime example of this is pepsin, which is secreted in the stomach by chief cells. pepsin in its secreted form is inactive (pepsinogen). however, once it reaches the gastric lumen it becomes activated into pepsin by the high h+ concentration, becoming an enzyme vital to digestion. the release of the enzymes is regulated by neural, hormonal, or paracrine signals. however, in general, parasympathetic stimulation increases secretion of all digestive enzymes.
gastrointestinal physiology