good morning good afternoon this is Dr Das shavo hope you're all doing well and let me move that over we are starting with chapter four now I'm going to try to go a little bit faster uh the first one I did it kind of took a long time and some of this you should already know okay so we looked at cells we talked about that we're going to look at the alteration of cell and tissue biology so you probably recognize some of these changes and these are adaptations that are reversible that can happen we're going to go through them quickly you're very aware of atrophy anyone that you've worked with in a nursing home has undergone that that's where the cells shrink because they're not being used hypertrophy is when they grow like you're lifting weights hyperplasia happens when you get more cells like a catalyst metaplasia and displasia are a little funky a little difficult to tell apart okay metaplasia is when cells start to change and not look like the original cells but they are metaplasia is when one cell type replaces another so they look very similar okay but that's the subtle difference there and you could go through these uh slides on your own I've given you the basic gist of them different ways that they can change okay excuse me a big one that we'll see is metaplasia in um really this should say upper respiratory cells okay when you get down to the bronchioles it gets more um to a different type of cell but it's neither here nor there you probably know these cells as being ciliated these line your upper respiratory tract and people who smoke can change these into either dis plastic so they're still quotequote the same cells but but they do not look the same do they okay these nice ciliated cells don't have cyia anymore excuse me and metaplasia starts to change into different types of cells but you lose oselia and this is why smokers cannot get flum out and people who have ciliated cells in their respiratory tract and all cilia art are these little hairlike cells that push the Flem that we get from the respiratory tract up and out and it actually goes down into our stomach and we chew it up well our stomach ches it up okay people who smoke don't have this cyia and so the cells change don't have cyon and you cannot get out that Flem they hack it up they have to cough it out all right so some cells can recover some are irreversible and those cells can go through processes and eventually die just like those respiratory cells if a smoker stops smoking it can go go back to ass ciliated cell and here's those steps through it hypoxic injuries so hypo means decreased toxic oxygen so this is the single most common cause of cellular injury and it could be caused by a multitude of things reduced supply of blood people who can't breathe as well okay um copds they can't get good oxygen in they can't get the old air out so they can get hypoxic issues okay but we're talking about injuries here I'm just trying to give you some ideas um CO2 uh co uh poisoning carbon monoxide poisoning would be a perfect example of hypoxic injury loss of hemoglobin loss of blood okay loss of um blood due to a blood clot poisoning okay all of these are examples so esia quite often we will see because of a blood clot we have a picture a little bit further on in noxia so a as a prefix means without just to give you some ideas of prefixes so that's a total loss of oxygen so esei reperfusion injury you're all familiar with this probably so you have a blood plot that lodges somewhere it eventually gets taken care of or dislodges and goes somewhere else that tissue gets reperfused so excuse me could be inflammation could be a blood clot okay could be um fat in the vessels okay oxidative stress can cause fat in the vessels that closes that vessel down there's a multitude of injuries that can cause that so anoxia you can see right here thrombus this poor little cell cannot get what it needs so it swells um because it doesn't have a balance doesn't have the right amount of good stuff to get into it to function correctly and eventually if it does not get the thrombus dislodged soon enough it'll get reused now it's damaged it can't function properly and it can allow a bunch of bad stuff in there if it hasn't already broken open and lost its content okay so oxidative stress is when we have what are called free radicals which are just charged um atoms or electrons okay that damage tissues and this is why we have antioxidants okay we have antioxidants in an attempt to try to counteract these free radicals with oxidative stress and they could cause a multitude of injuries so lipid peroxidation can happen oh I had a little drawing tool and I don't know where it went right so that lipid perx oxidation can actually cause a depositing of fat on the inside of vessels which can grow and grow and grow and grow and start to harden vessels and then blood clots can attach to the inside of that that'll close down that blood vessel so blood can't get Beyond it and we get a thrombus which attaches to it so it would be just like this picture except there would be fat lining that blood vessel and the thrombus or those blood plots like to attach to that fat okay protein alteration most of the structures in our body are created with proteins so if we get damaged by these oxidative stresses it can damage the structures of our body finally we could get damage to DNA itself which is not good that can lead to cancerous cells and you should remember that mitochondria are the powerhouses of the cell if you get damage to those you get damage to the ability to create energy okay okay and this breaks it down in a picture we can also get toxic um substances from our environment which can be carcinogenic also which mean create cancer mutagenic means it can mutate the cells which can also eventually lead to cancer over you know some prescribe drugs have side effects as well if you look at the side effects on the back you're like holy cow but you know I always ask my primary care and she's like well yeah they have to list everything that happened in the studies but there are some drugs with side effects and you got away your benefits and your negatives right okay um so environmental Texans toxins heavy metals ethanol regular old alcohol drinking alcohol in high amounts can cause tissue damage we'll talk about kind of a progression of that later unintentional potential injuries you guys all know this you've probably seen a million examples unfortunately if you've working in the ER I I'll let you read through those on your own I'm so sorry excuse me infectious injury um this one I wanted to talk about okay so immunological and inflammatory injuries so inflammatory responses fagos sites are little um cells that our body creates that come from what are called monocytes and they eat up substances now keep in mind that that um is true of infectious agents as well as worn down cell byproducts okay so biochemical substances histamine is a substance that releases that draws inflammatory um substances to the area of injury so if I get a stabling the histamine releases saying whoa something's wrong here bring some white blood cells here to respond to this injury now antibodies are longer acting substances that will be created with an injury I should say more an infection our body will recognize that infection in the future and be able to fight it again if we get it lymphokines are substances that are released that draw white blood cells to that area complement system is a very complicated system that says there is an injury in this area and it starts a whole Cascade of responses to bring substances to that area to fight off infections proteases are enzymes enzymes AES is a suffix that says um it is an enzyme that breaks down proteins that are not needed membrane alterations once we start to damage or have an area of injury or inflammation or infection in an area the membrane of those cells don't function as well as they would if they were nice and healthy most common cause of cell injury now I'll tell you I kind of hesitated on this one myself but if we look back it's a okay and this is something you need to start looking at in these notes there it is hypoxic single most common cause of cell injury and I think it's because of plotting um you know due to es schema um would be a good example maybe they bring in hypoxia from respiratory issues as well so you got to look for that because those little things are in the notes okay once again I would also read through this and know this because I feel like some some questions may be taken from there okay so cell injury you could get accumulations you could get substances that will accumulate in those cells you could get water proteins lipids I'm going to talk a little bit about lipids and that process carbohydrates endogenous substances are substances that our body makes exogenous substances are poisons and substances from the external environment so accumul ations that happen inside of the body or I'm sorry of the cells so we get an accumulation of abnormal substances because something's going wrong inside of that cell some sort of activity is not happening and we are getting we may have those little lomes inside the cell with enzymes to break down gunk in the cell something's going wrong so it could be that that tissue is getting old or cells are getting old we've got some sort of poison or what I'm going to go through is fatty liver I think that is a great example so what happens in people let's say who um are morbidly obese and or drink too much you can actually in the liver get a deposition of fat so the liver can only teach so much stress it is super resilient I mean super super super resilient but after a while it gets tired and you could start start to get a deposition of fat in that liver eventually the cells with these depositions of fat don't function they can't get rid of substances they can't bring in good substances as well their SE cell membranes start to get damaged it eventually starts to turn into scar tissue and bingo bingo you have sosis so I think that's a great example of cell injury and this shows other things you know proteins can be stuck in there lasal storage diseas is genetic um issue where they cannot function as well with those little lomes and you could get scar tissue in there and exogenous materials are um like ingested poisons for example that we can't get out okay eventually you could get cell death cell death leads to apoptosis if we have too much we eventually have tissue death okay so apoptosis is a normal process that can happen in cells all over the body it's happening in you right now you're getting old cells they're not functioning well they get destroyed um we have phagocytes that come in and eat up those dead tissues and get rid of them okay if it gets to be too much our body can't get rid of it and we get necrosis so there's different types of necrosis and I think it's good to review these and you probably are aware of some of them okay so coagulative necrosis is when proteins denat and protein denaturation is when proteins the amino acids which create proteins break down and you cannot restructure that protein perfect example is an egg okay egg is a very good source of protein what you cook it can't turn it back happens to the proteins in our body now this happens in the bloodstream and you could get blood clots or you could have tissues break down in CL blood clots and you could get what's called an infar which is a block of a blockage of a blood vessel okay so coagulative necrosis we have had a blockage of a blood vessel and what's happened is this heart tissue I think so a heart yes has gotten damaged and the muscle proteins in that heart have broken down and now created coagulative necrosis okay so an infar can be caused by that blood clot and then you could get coagulative necrosis of the tissue itself liquefactive necrosis this will happen in the brain okay the brain breaks down and the neurons and gal cells which are the supporting cells are digested they become soft and almost liquefied okay can happen from a bacterial infection if you are asked about necrosis it's in the brain it's going to be liqu effective casus is a combination of these two casus always grosses me out happens in the lungs most frequently and you get this cheesy like substance okay fatty will be in fatty acids and it creat creates an opaque and chalky white appearance okay gang graness is something you're probably uh familiar with it's death of tissues due to hypoxia can be dry can be wet you know you could see the explanations in there and it'll get cold swollen and black black so this would be genrus here if if you look at that once again read through that apoptosis we spoke about right so there's physiologic verses pathologic physiologic is just old cells getting destroyed broken down eaten up pathologic will be if there's some sort of disease process autop fasi is auto cell fasy chewing up okay uh you have substances that are in cells there are delivered to those lomes those little packets of enzymes in cells and we can break those down okay so aging and altered cellular and tissue biology I'm going to let you read through that on your own okay you can do this question once again practice reading every word of the question rereading it reading every word of every answer and going through I think that one's pretty self-explanatory now I found this um a little bit confusing so I did bring up the different steps so par Morse algar Morse rigor mortise liver mortise P for Cas I think we've got these okay but I did bring up a little picture because that is something I thought that would be [Music] helpful oh here we go all right so po mortise is becoming pale maybe that's something you know morol refers to death I thought this was a great picture so that happens fairly quick quickly at the beginning algr mortis is cooling of the body um and I like this because it gave kind of the breakdown um that's 12 hours after death the body will start to cool and reach room temperature and if you watch CSI they probably have thrown these turns terms around rigor begins when the muscles start to tighten up and what happens is you actually need energy to break the bonds of the connections of muscles so if you contract a muscle in order to relax it you need energy believe it or not you don't have energy anymore so the muscles all tighten up and the reason they start to let go eventually is the actual muscle tissues break down and they will loosen up so that's a process of rigor mortis liver mortise is the blood that will pull in the lower areas liver mortise will happen 1 to two hours after death 6 to 8 hours mean that it's permanently staining the skin and it won't change like I said maybe this is the uh this is you know this but wanted to go through it um you could read about the stomach contents and then putri for catas is going to be when the body actually starts to break down okay and that bacteria comes out and then it'll decom decompose um obviously that is variable according to what happens to the body if a go gets preserved or not and then skeletonization is the process of and you know on weird things on rdit where you can see different bone collectors and with the decomposition they'll actually put them in with bugs to eat substances off to get down to the skeleton and then the preserve that skeleton which I know a little weird but anyway and that brings us to the end of this chapter as I promised this was a little bit quicker if you have any questions please don't hesitate to reach out have a great day