hey guys it's metagosis perfect net is where medicine makes perfect sense let's continue our microbiology and infectious diseases playlist today we compare between exotoxin and endotoxin EXO means out because it's a toxin that is secreted out of the bacterial cell conversely an endotoxin and domains in is part of the membrane that is within the bacterial organism as long as this bacteria remains alive this toxin its membrane is not just gonna leave it and jump away it shall remain Endo so that's the basic idea exotoxin the toxin is literally released to the EXO but endotoxin the toxin is part of the membrane it's the outer membrane of the gram-negative bacteria that's why this bacterium is Pink do you remember the outer membrane of the gram-negative bacteria it was the lipid a lipopolysaccharide the toxin is part of me will never believe me it's on my dead body only after you kill me and destroy everything within me only then will the toxin leave let's review what we have discussed before bacteria versus Humans prokaryotes versus eukaryotes bacteria do have a cell wall humans do not as for the cell membrane or plasma membrane or cytoplasmic membrane both of them have it so here's the cell structure of a bacteria cell wall on the outside cell membrane deeper and in the cytoplasm and not a nuclear membrane but no clear material what was in the cell membrane lipid as for the gram-negative bacteria we have an inner membrane and an outer membrane and between them there is the periplasmic space the outer membrane is above the cell wall it's on the outside what's the structure of the outer membrane very similar to the inner membrane we're talking lipid by layer and we compared between gram positive and gram-negative structure before please pause and review just a reminder that the gram negatives have an outer membrane but gram positive usually do not in that outer membrane there is lipid by layer and we have lipopolysaccharide endotoxin we talked about polysaccharide o which is a weak antigen and lipid a which is pyrogenic I.E causes fever and don't forget that lipid a stimulates in a look in one which cause fever inflammation and tnf Alpha which recruits white blood cell and activates your endothelium so this is what we mean when we say endotoxin I.E something unique to the gram negatives first we'll talk about the exotoxin then we'll talk about the endotoxin and then we'll compare between the two exotoxin I'm really is from the bacteria I could be gram positive or gram-negative bacteria who made me an order from the genetic material like geoplasmid or prophase they carry genes which code for proteins the protein is the exotoxin it's a polypeptide and structure since it's called the exotoxin it is released and it's going to travel from the release site to the Target organ however be careful because high temperature can inactivate the exotox usually we give it a name that is very similar to the name of the disease that it causes example Shiga toxin is an exotoxin it causes shigulosis osis means condition another example Anthrax toxin causes Anthrax botulinum toxin causes botulism some of these exotoxins are lethal such as botulinum toxin only a few nanograms per kilogram of your body weight can kill you the good news is it is heat labile which means raising the temperature can kill this very powerful toxin so if you're not sure if you have doubts about your tuna can any afraid that the tuna can might be compromised or dented and you don't want to get botulism just cook the food just boil the contents and you will inactivate the exotoxin because knowledge is power exotoxins are strongly immunogenic and antigenic and for this antigen you'll make an antibody called antitoxin it has a variety of different mechanisms some of them cause ADP or hyposylation what the flu does that mean it means bring me a molecule of ADP and a molecule of ribose oh by the way where did you get them from from your NAD plus and then I bind these two together to make ADP riboselle elongation Factor 2 which can lead to cell another mechanism is to disrupt the cell membrane by making pores which is a hole in the wall I mean in the membrane or it could cause lysis of the cell such as phospholipation this is how the alpha toxin of clostridium perforingins which we'll talk about in a later video works a fourth mechanism is hemolysin which causes hemolysis destruction of blood cells some exotoxins are like the Incredible Hulk super antigens they stimulate a third of your T lymphocytes inducing them to release lots of cytokines this cytokine storm can lead to multi-organ failure shock and death one common example of exotoxin is a b toxin what does a mean active this has enzyme activity this is the toxic part of the toxin B is just for binding to bind to your cell receptor cause end endocytosis of the toxin so that a can start working and causing trouble next endotoxin gram negative only because this is part of the outer membrane specifically lipid a it's part of the membrane unminded body it's not going to leave me unless you kill me sometimes it's released during cell division but that's an exception the rule is here usually does not cause formation of antibody there is no antitoxin for the endotoxin and as you can imagine making vaccines against this I.E toxoids against this is very difficult unlike the exotoxin which can lead to disruption of the cell membrane license of the cell hemolysis of your red blood cell ADP ribosylation I.E giselian mechanisms all the endotoxins have the same freaking mechanism which is the picture of gram-negative sepsis the patient has fever hypotension and then thanks to the better receptor reflects the hypotension will cause tachycardia and you will have volume depletion extra cellular fluid volume depletion you might even bleed from your gut which causes more volume depletion why do I have all of this because of these molecules interleukin-1 in a look in 6 and look in 18 and tnf Alpha don't ever forget that interleukin-1 is pyrogenic it causes fever moreover lipid a will activate two opposites it activates Factor 12 this is coagulation Factor number 12 also known as Hagman factor which causes clots because it's a coagulation Factor coagulation means clots and it also activates fibrinolysis which means breaking down clots you're making clots you're breaking down clots what's the name of the disease where you keep making and breaking clots disseminated intravascular coagulation where you bleed from every wound bleed from every scratch bleed from every orifice I have a separate video about DIC in my bleeding and coagulation playlist now let's compare exotoxin is released into toxin is not released it's part of the outer membrane it's the lipid a lipopolysaccharide exotoxin is polypeptide I.E protein-like or in the protein family but endotoxin is in the lipid family exotoxins could be released from a gram-positive or gram-negative bacteria but endotoxins only gram negative if it's a polypeptide if it's a protein usually proteins are more active than anything else in your body it's strongly immunogenic I.E you will make anti-toxins I.E we can use toxoids as vaccines against these doofuses conversely since lipid a is a lipid it's weakly immunogenic therefore there is no antitoxin no toxoid no vaccine exotoxins have many different pictures and many different different mechanisms but endotoxin only one freaking picture of the gram-negative sepsis who coded for this the bacterioplasmid or bacteriophage but since the endotoxin is part of the bacteria itself it has to be the bacterial chromosome itself the big boss exotoxin fortunately is heat unstable hate is gonna kill it therefore hate the tuna before you eat it when in doubt when in doubt boil it out but the endotoxin is heat stable examples of exotoxins are here example of endodoxin is here you can say E coli causing gram-negative sepsis you can say meningococci causing meningocoxemia remember to integrate this with Waterhouse friedrichsen syndrome which is an acute edisonian crisis when your adrenal gland leaves the chat if you like this video you will love my and diabetics course comes with 40 videos about some doozy pharmacology at medicosisperfectsnetis.com I also have a surgery high yields course an emergency medicine high-yield course all at medicosisperfects netiz.com thank you for watching please subscribe hit the bell and click on the join button you can support me here or here go to my website to download my courses be safe stay happy study hard this is medicosa's perfect snails where medicine makes perfect sense