Stomach is the J shaped muscular organ present in the GI Tract which is connected superiorly with Oesophagus and inferiorly with small intestine.
Parts of Stomach
1. Fundus – It is the upper part of the Stomach and this part is connected with the Oesophagus by Cardiac sphincters .
2. Body – It is a middle portion of the Stomach .
3. Antrum – The lowermost part of the Stomach.
4. Pylorus – Pylorus is a ending part of the Stomach .
Layer of stomach-
- Mucosa – It is innermost layer of the Stomach . It contains glands that secrets the digestive juice that called Hydrochloric acid and pepsin .
- Submucosa – It is second most layer of the Stomach from inside. It contains the blood vessels , nerves and lymphatic vessels.
- Muscularis – middle muscular layer of the Stomach through that peristalsis movement perform.
- Serosa – Outermost layer of the Stomach.
Hormone secreted by Stomach
Phases of digestion
1. Cephalic phase – In that phase food sight , smell or thought stimulate the neural impulse that travel to hypothalamus and amygdala .
2. Gastric phase – In that phase gastric secretion stimulate during taking food .
3. Intestinal phase – In that phase nerves stimulate when food enter into the intestine .
Stomach Cell and their secretion –
Goblet cell – It secret the mucus that protect the stomach lining.
Parietal cell – It secret Hydrochloric acid ( pH is 1.5 to 2) . It requires for the activation of pepsinogen.
Chief Cell – It is located deep in stomach mucous lining and secret proenzyme pepsinogen that with acidic environment convert into pepsin .
D cell – D cell present in open type in antrum and closed type in oxyntic mucosa and it’s main function is to secret somatostatin . Somatostatin main function is to reduce the pancreas hormone secretion include glucagon and insulin .
G cell – It is a G- cell or gastrin cell that found in stomach and duodenum and it’s main function is to secret Gastrin cell . Gastrin cell stimulate secretion of Gastrin acid (HCl) by the parietal cell.
Function of Stomach
1. Storage – Our stomach store food for 2 to 4 hour after that it release it into our small intestine . But storage is also affect by several factors as like –
- Sex – Female take more time for storage of food into their stomach in comparison to male .
- Type of nutrition mean fat or protein .
- Volume of food taken
2. Mechanical digestion – Due to peristalsis movement there is food breaking start .
3. Chemical Digestion – In that due to enzymes there is breaking down of food larger compound into smaller ones .