Wall Structure of the Large Intestine

00:01 Let's just have a look at the whole structure in brief. And again there's a lot more detail in various histology courses that you should engage in. But just briefly as other parts of the GI tract, we have the basic structure of the mucosa, the submucosa, we have a muscular layer, we have both circular and longitudinal layer. Remember the longitudinal layer of muscle is only occurring at the teeny space and then the serosa which is really the outer layer of peritoneal covering. Let's just have a look at the mucosa because as ever there's going to be a layer of epithelium which is highly regenerated and it's quite an aggressive position on the outermost layer of the wall of the colon where food is actually just constantly kind of churning against the wall and that can lead to some of these cells leaving. In between each of these semilunar folds which we can see, we have these various colonic crypts and that's where the various enzymes and various products and the mucus that is released from the cells within the epithelium, that's where these are discharged into those crypts and then they can enter into the lumen. We have the lamina propria which is obviously the important aspect where we have lots of solitary kind of lymphoid nodules and also various small blood vessels passing into the spaces so they will be occupying this space here. You then have the muscularis mucosa occupying a lot of those blood vessels that are running alongside the wall of the large intestine.