Hello students, this is a short lecture on membranes. So we've been talking about epithelial tissues. And so membranes are thin sheets of um tissues that line our surface cavities. And so they are usually composed of epithelial tissues plus or minus some connective tissues. And we're going to talk about connective tissues next. So this is kind of a link to that to that. Sometimes they also may contain some smooth muscle. So we have different types of membranes. Um but what is the function of our membranes? So membranes line cavities. They can be barriers. They can protect um as in immunity. They can make secretions. They um can anchor organs. So membranes um hold things in place. They can reduce friction. Um so allow things to grow and slide past each other. and allow for movement. Um we have different types of membranes in the body. We have true membranes and membrane like structures. So our true membranes are going to be the cirrus membranes in the body. So like your plural membranes or your paritonyium and your synovial membranes which are your joint membranes and then your membrane like structures. So, your mucous membranes, the membranes laying in your mouth, and your continuous membrane, your skin, which is what you see on me, um or you see when you see another person that's old, the skin that you see um like but not like membranes but not a true membrane. So, we talk about mucous membranes. Um these line all the p all the openings to our body. They are um they are layers of epithelium with a basement membrane. Okay. Occasionally there's some smooth muscle in there. So they are are membrane like and they are they are mucosa. So they are and moist and they are there to um maintain moisture to those cells and protect so that that mucus traps pathogens. There's usually local antibodies in there as well and prevent invasion of things. The mucus also can help lubricate um like if there's food going in the mouth um and like help move like food in the GI tract for instance depending on what the function is. And um as as as these linings they're there to protect Um sometimes the are we can have inflammation so abn abnormalities with these membranes. One example of this is something called friction rubs which you can actually hear or or you can have pain with and the cirrus membranes in the chest or the heart, the paricardial sack, the plural membranes or the paricardial sack actually get inflamed. And when they get inflamed, they tend to stick together. And so think of it like when your hand is is rubbing across a balloon. It kind of it it makes a loud sound. It kind of goes right rather than moving smoothly. If there were like water on the balloon, it would just slide across. When it gets inflamed, there's less fluid there and it gets sticky and it it sticks together and it's painful. And you can actually hear this as the as the chest expands and contracts during breathing. You can hear that rubbing when you're listening to the chest during thoracic oscult oscultation and this can also be painful during breathing and this can resolve with treatment. So it can be it can be inflammatory um and infectious. So membranes again you've got your cutaneous membrane which we're going to do a whole chapter on. You've got your um mucous membranes and the mouth. You've got your synenovial membranes which we'll talk about in our in our um bone lecture chapters coming up and you've got your um cirrus membranes which are th those lining your cavities and again this is more anatomy but I just wanted to touch on those a little bit before we moved into connective tissues. So if you have questions give me a ring make sure that you review your anatomy as well. You do have some extra anatomy slides and our next lecture is going to be on connective tissues. I'll see you there.