hello everyone so today we begins with the physiology of gastrointestinal tract and this is the fifth video in in this video we are going to cover this stomach their secretions it so figures on its lower end opens inside the stomach this is the cardiac region of the stomach this part it is known as fundus of the stomach this is body of this stomach this is the entrance but it is known as pylorus and in the pylorus there is a pyloric sphincter this is the angular node inside the stomach walls there are numerous folds these are known as blue guy gastric functions or the functions of the stomach reservoir for control release of digesta into the small intestine mixing of the food mechanical breakdown of the feed for food hydrolytic digestion by acid and enzymes mainly protein digestion it kills the bacteria secret intrinsic factor which is needed for victim individual absorption form on products and carefully controls emptying of contents to the small intestine so all these are the functions of this stomach most important my equation so this is the mucosa of the stomach in the mucosa there are different type of cells surface mucous cells which secretly mucus mucus make cell which secrete the mucus this is the parietal cells parietal cells secret hydrochloric acid and intrinsic factor cheap cell cheap cells secrete pepsinogen and gastric lipase and hormone producing jisun secrets hormone gastrin so this 3 cell and their secretion is most important parietal cell secrete hydrochloric acid an intrinsic factor cheap cell secret pepsinogen and gastric lipase form on producing G cell secret hormone gastrin all right stomach secretion it is around 2.5 to 3 liters per day with a pH of 1/2 tube inside the stomach secretion the most important content is the hydrochloric sa for HCl which decreases the pH around 2 to 3 it kills the bacteria it activates the pepsinogen which is a proteolytic enzyme to pepsin helps in iron absorption second mucus there are two different types of mucus secretion in soluble mucus and soluble mucus which protects lining from the acid and enzymes and it forms a barrier so there will be no authorization of the gastric mucosa with the help of this proteolytic enzymes and it also act as a lubricant pepsinogen the most important proteolytic enzyme inside the stomach and it is secreted in the inactive form and it is activated to pepsin by at Ciel hydrolysis protein to Proteus captain's and polypeptides so it is the function of pepsin lipase in some species intrinsic factor gelatinous lysozymes and electrolytes so all these are the stomach secretions stomach secretions will be asked as a short not so this is the parietal cell and how the Etzel secretion what is the mechanism behind the HCL secretion that is what I am going to explain right now two simple molecules co2 and h2o combines to form h2 co3 with the enzyme carbonic anhydrase this h2 co3 divided into h plus h co 3 - now this H+ ion goes inside the lumen of the stomach via h plus k plus 80 PS pump these s plus ion goes inside this stomach lumen via h plus k plus ATPase pump right okay now this su 3 - and coming out with a replace of cl minus ion via hco3 minus CL - active and reported transport these ezio 3 - coming out of the parietal cell with the help of CL - empty Porter transport and this transporter is known as hco3 minus CL - active and tip water transport now this hco3 minus iron goes inside the blood vessels so it is responsible for postprandial alcohol tied as well as ID alkaline urine so it is the most important wire question what is post prandial alkaline tied so due to release of H+ ion inside the lumen of the stomach every news on H+ ion there is a release of hco3 minus and into the blood which is responsible for post prandial alkaline tight alright now whatever the CL minus n enter in this it will goes inside the lumen via CL minus channels this is the CL minus end enter into the lumen of Testim by CL minus channel so here h plus and Cl minus iron combines to form the HCL inside the lumen of the stomach so this is the mechanism how the HCL formation occurs in the lumen of the stomach and it is the most important now we already know what is the mechanism behind synthesis of HCl inside the parietal cells now functions of HCL kills ingested bacteria as protein digestion it activates pepsinogen into pepsin with the act of this HCl pepsinogen is converted to the pepsin but first pepsinogen have to be converted in pepsin by the HCL and later this pepsin also converts further pepsinogen into the pepsin provides the optimum pH for pepsin action which is around 2 to 3 pH stimulates secretion of hormone that promote the flow of bile and pancreatic juice so it is also important function of HCL so all these the functions of HCl inside the stomach regulation of gastric secretions there are three phases in the regulation of gastric secretions cephalic phase gastric phase and intestinal phase so first we begins with the cephalic phase which is mainly nervous phase in the cephalic phase condition reflex and unconditioned reflex conditioned reflex stimulus sight smell thought of the food center brain indifferent along the vagus no it is going to increase the citizens of the stomach via the vagus no unconditioned reflex stimulus taste of the food center medulla oblongata indifferent along the vagus no so with the help of condition and unconditioned reflex there will be the release of gastric juice by the different runs to the vagueness no now the second one gastric phase stimulus food distending the stomach that means entry or presence of food inside the stomach Italy stands the stomach and it is a stimulus for the gastric phase of the release of the gastric secretions nervous through Baker's no continued gastric secretion and motility of this stomach and hormonal with the help of this gasoline hormone produces secretion leeching acid and pepsinogen remember I already told you that G cell of the stomach mucosa secret gas stream all right third phase intestinal phase of the gastric secretions stimulus food distending the duodenum it's obvious thing that whenever the food enters into the duodenum it initiate the intestinal phase of the gastric secretions nervous it inhibits gastric secretion and motility so inside the intestinal phase it is regulated by a different type of nervous system and it it inhibits gastric secretion and motility and hormonal where the release of secretin and cholecystokinin these are the hormones which are released from the different type of cells of the intestinal mucosa from the duodenum and small intestine and it inhibits gas stream release gastric secretion and motility so here the important thing is that in the cephalic phase it is going to stimulate the gastric secretion gastric phase obviously there is a need of gastric secretions so it is stimulated but in the intestinal phase once the food has been entered into the duodenum which is a first part of small intestine there is no further need of the gastric secretions as well as gastric motility so in the intestinal phase these hormones as well as mouse which is going to inhibit the gastric secretion and gastric motility now the gas train which is a hormone remember hormone is a substance which is secreted by the different type of cell directly into the blood right there substance unknown as hormones so gastrin is a hormone which is release from the G cells of the stomach directly into the blood via the blur it again acts on the stomach how we are going to see it is secreted by G cell of antral glands secreted as pro gastrin converted to destined by HCL or and food products functions of the gasoline it stimulates growth of the mucosa it stimulates motility of the stomach small effect on old ladle contraction so these are the functions of gastrin Jolene's are allison syndrome it's a gas stream producing tumor in that condition there will be the high level of gasoline into the blood factors affecting guesting secretion protein digestion products distension of pyloric Antrim vehicle discharge or gastrin releasing peptide g RP an acid in Antrim inhibits the gastric secretion so these are the factors which affect the gasoline secretion protein digestion products distension of the pyloric Antrim vehicle discharge or release of the gastric releasing peptide and acid in the antrum which inhibits the gastric secretions so these are the functions of gasoline which are the functions of gasoline it stimulate the growth of the mucosa it stimulate the stomach motility or gastric motility and small effect on the gold-medal contraction so that is all about the gastric its function and factors affecting the gasoline secretion so in this figure you are going to see how the stomach secretions are regulated by the nervous as well as hormonal factors so parasympathetic pre ganglionic now fibers with supplies to the stomach where a sympathetic postganglionic impulses stimulate the release of gastric juice from the gastric glands these are the parasympathetic preening no fibers of the vehicles no they going to stimulate the parasympathetic postganglionic fibers and there will be the release of gastric juice from the gastric plants whenever this parasympathetic preganglionic no fibers are stimulated whenever these vehicles no is stimulated now impulses of these vagus nerve stimulation also stimulate the release of gastrin which is a hormone and it is released from the G cell as it is a hormone it is released into the bloodstream via the bloodstream it again having the act or effect over the gastric mucosa gastrin stimulates gland to release more gastric juice and this gasoline again having the effect over the different type of cells of the stomach and it increased the gastric juice secrecy