[Music] AR Manan biology and Medicine videos please make sure to subscribe join the foring group for latest videos please visit Facebook Manan please like and here you can also ask questions answer questions and post some interesting things including your artworks and you can also change the quality settings to the highest Graphics in this video we'll talk about hydrochloric acid and how it is secreted what regulates acid secretion in the stomach and from this we'll see how peptic ulcers are formed and also why people have heartburns finally we will see what drugs can be used to help with these conditions we will Begin by looking at the gastrointestinal tract starting from the esophagus which comes down to down from the mouth and connects to the stomach the stomach then connects to the duodenum of the small intestines the stomach produces 2.5 lers of gastric juice per day because of this the Lumen of the stomach the inside of the stomach is very acidic about one about a pH between 1 and two the the esophagal spa is a barrier between the acidic stomach and the esophagus to prevent the acid from going back towards the esophagus and the pylorus fcta is the barrier between the acidic stomach and the dood denum we would not want acid from the stomach to go into the duodenum or the esophagus otherwise it might cause some uncomfortable able conditions acid that is secreted by the stomach helps in food digestion acid in the stomach is SEC is secreted as hydrochloric acid let's have a look at the cells of the stomach and where hydrochloric acid comes from and look at the overall picture of how hydrochloric acid secretion is regulated here we have the section of the stomach it can be divided into three main layers the mucosa on top the sub mucosa and the smooth muscle which is meant to be a lot bigger than depicted on this diagram and also we have a Sosa layer but that's not drawn the sub mucosa contains the vein and arteries to deliver and return blood to the liver the stomach have Crypts where different stomach cells are when we eat our nerves send signals that cause the parietal cells the to secrete hydrochloric acid which is necessary for food digestion here we also have OC Chopin cells around this area which secrete histamine histamine in this case promotes hydrochloric acid secretion by the parial cells there are also G cells G cells are Endocrine cells which secrete gastrin which also promote Hydrochloric secretion hydrochloric acid secretion by the parietal cells then we have another endocrine cell the D cells these cells secrete somatostatin somatostatin actually inhibits hydrochloric acid secretion by inhibiting uh the G cells from releasing gastrin by inhibiting uh the parial cells from creting hydrochloric acid and by inhibiting anoch chromin cells to secrete histamine now of course there are other things that regulate hydrochloric acid secretion and we'll look into it in more detail soon probably the most important cells in the gastrointestinal tract are the cells on the top and these are regular epithelial cells or the mucus cells and they produce mucus which helps protect the stomach from bacterial infection as well as from the acidic environment of the stomach another type of cell worth mentioning in the stomach are the chief cells that secrete pepsinogen necessary for protein digestion okay let's have a closer look at how hydrochloric acid is secreted and how it is regulated by all these other cells and surrounding it so here we have some stomach cells we have the D cells the G cells and here we have the parial cells the parial cells secrete hydrochloric acid remember and then we have the mucus cells here we have the Intero chromin cell abbreviated e l the parietal cells secrete hydrochloric acid into the Lumen of the stomach which is situated here through a proton pump sort of thing the prial cell secrete hydrochloric acid by secreting hydrogen ion and in exchange for potassium ion and then it will secrete this potassium ion again together with chloride ion thus forming hydrochloric acid in the stomach simple HCL is hydrochloric acid and helps in food digestion so what stimulates the process of secreting hydrochloric acid well as we mentioned ecl secretes histamine which bind onto histamine 2 like receptors on the pariot cells which will stimulate this whole process to secrete hydrochloric acid the G cells which are Endocrine cells will secrete gastrin into the bloodstream from here gastrin will bind onto gastrin receptors on ecl which will stimulate histamine release which will then stimulate hydrochloric acid secretion by parial cells Gaston also bind onto gastron receptors on proctyl cells which will stimulate hydrochloric acid secretion um the vagus nerve part of the parasympathetic nerve innervating the stomach area will secrete acetylcholine which will bind onto muscarinic receptors on both parial cells and Intero chromin cells which will all promote hydrochloric acid secretion so all these were promoting hydrochloric acid secretion the cells and mechanisms that inhibit hydrochloric acid secretion include the hormone somatostatin which is secreted by the D cells so somatostatin inhibits basically the hydrochloric acid secretion also inflammatory mediators such as prandin E2 and prandin I2 derived from arachadonic Acid inhibits um hydrochloric acid secretion arachadonic acid through the enzyme Cox can synthesiz can synthesize pranon E2 and pranon I2 which binds to prostag glandon receptors which inhibit hydrochloric acid secretion by the prial cells prostag glan E2 and prostagl I2 also binds to and activate mucous cells to secrete mucous and bicarbonate these are the most important substances that have a negative effect on Hydrochloric acid in the Lumin of the stomach because mucus and bicarbonate essentially neutralize the acid which prevents the acid from damaging the stomach itself so mucus is very important in this respect now we know how hydrochloric acid is regulated and balanced in an overall General picture here let's see what happens when there is too much hydrochloric acid secretion when there's just heaps of hcls essentially if there's too much hydrochloric acid being secreted and there's not enough like defense against this acid it can cause peptic ulcers let's zoom into this peptic ulcer here is a diagram a diagrammatic representation of a peptic ulcer here is the mucus layer submucosa the three muscle layers and the Sosa peptic ulcers are eroded areas of the mucosa caused by digestive juices and acid which may be perforated or bleed peptic ulcers are particularly uh in the stomach but ulcers can also occur anywhere along the gastrointestinal tract including the durum the pathophysiology of peptic oos are straightforward if there is an infection by bacteria such as helicobacter pylor this can cause peptic ulas and of course if there's an imbalance between mucus damaging products such as pepsinogen and hydrochloric acid and the protective products such as bicarbonate and mucus this can cause hydrochloric acid so if there's less mucus and there's more acid of course you would damage the mucus layer causing peptic ulcers now causes um of peptic ulcers can be induced by stress smoking and non-steroidal anti-inflammatory drugs andad now you might think how would nads possibly do this well remember down here pranin E2 and pranin I2 normally inhibit Hydro choric acid secretion nads work by inhibiting the enzyme Cox which is responsible for making prandin E2 and prandin I2 so if we inhibit the the synthesis of these prostaglandins it would mean that more hydrochloric acid can be secreted which can cause peptic ulcers another condition that can arise from Acid too much acid or acid itself is a phenomenon known as heartburns which don't actually involve any hot damage or maybe but it doesn't it's actually better called gastric acid gastric reflux gastric acid reflux is when we have backflow of stomach content acid upwards towards the esophagus the esophagus lacks the protective lighting of the stomach therefore acid reflux can cause pain inflammation and damage gourd also known as gastric ESOP FAL reflux disease is an extreme case of gastric acid reflux some people call it gird because different English-speaking countries require different abbreviations which is ridiculous anyways gourd can be associated with certain food medication or conditions and in gastric acid reflux there can there can cause the phenomenon heartburn and this can occur as much as 20% in the gourd cases so so gastric acid reflux up the esophagus can cause heartburn the pathophysiology of G is not fully understood but it's most probably due to the disturbance in normal gastric gastric reflux barrier or the weakening of the esophageal sphincter which is a barrier between the acidic stomach and the esophagus okay so now that we know about gastric acid reflux and peptic ulas how would we treat it well we can either neutralize the acid or prevent the acid from being secreted we can use an an anti acids such as a com combination of magnesium and aluminium salts which will neutralize the gastric acid hydrochloric acid and hence raise the ph raising the pH to about three will neutralize most of the acid anti acids are usually anti acids are usually short acting so that's neutralizing the hydrochloric acid but we can also prevent hydrochloric acid from being secreted for example the proton pump inhibitors that end in prazol such as o om prazol will irreversibly bind with and block proton pumps these are well tolerated effective and has a longlasting effect there are also histamine 2 blockers such as sodide which inhibits all histamine 2 receptors therefore uh they they have a shorter action duration than proton pump inhibitors and they they have they are found to have more of affinity to block H2 receptors in the stomach even though there are H2 receptors all over the body we can also inhibit the actions of ayic Coline from the parasympathetic nerve endings by using atropine but these have problems in itself so I hope you enjoyed the physiology the disease and pharmacology video on gastric acids thank you for watching