hello this is the mucosa of the vermiform appendix we have the crypts here which are lined by columnar cells and you can see that they have these goblets and in between we have the lamina propria we're going to zoom into the lamina propria to look at all these cells here so that you can familiarize themselves with the morphological appearances of different types of leukocytes or white blood cells at this increased magnification you can see a lot of relatively small nuclei and a lot of cells with extremely reddish cytoplasm so think about what these cells that the red cytoplasm could possibly be at this magnification we can see that very strikingly there are these cells with extremely reddish cause granular cytoplasm these cells also have a by locked nucleus here of resembling like a pair of glasses and these would be the heels and the fills remember there are types of granulocytes which means they have a granular cytoplasm and a locked nucleus there is another type of cell here with a multi looked nucleus and again here and these would be neutrophils neutrophils are your main layers in acute inflammation if you recall there are a lot of other cells in the background such as this cell over here which does not have cytoplasmic granules not visible on light microscopy and another such cell here as well as here so these cells have relatively round to slightly irregular nuclei and very scant cytoplasm and these are lymphocytes here at higher magnification we can see that there are a few cells like this with more vital plasm with a very eccentric nucleus that's placed to one side almost touching the side of the cell membrane on one side the cytoplasm a sort of peel publish and there is a pale pinkish area here right next to the nucleus which we call a Hoff so this cell is a platinum a cell there is another plasma cell here you can't really see the cytoplasm so well but you can imagine that the chromatin really looks like a clock face because it sort of read eating from what's in and this classical pattern is seen and clashed myself you can see another plasma cell here with the purplish cytoplasm the perinuclear HOF and the clock face chromatin in this different area there are actually quite a lot of plasma cells you can see a couple here another one here a couple of plasma cells here here as well as here and a lot of cells in the background are lymphocytes so here are several lymphoid follicles with the paler germinal centers and the darker mental zones and I'm just going to zoom in to show you the different appearances of lymphocytes here we have the germinal Center and we have the outer mental zone all of these cells are lymphocytes and you can see that in the germinal Center there are larger lymphocytes and in the metals on the lymphocytes are smaller so here on this lower half is the germinal Center and on this upper half is the mental zone and you can recognize the lymphocytes as being quite small with browns of slightly irregular nuclei hardly any cytoplasm at all and no visible cytoplasmic granules and lymphocytes in the general Center Center are a lot larger and the nuclei tends to be a little bit healer with more prominent nucleoli so back to low power this is actually a case of acute appendicitis and I'm going to show you the wall of the appendix typically in acute appendicitis the wall is infiltrated by the acute inflammatory cells which principally comprise neutrophils so here is the wall and here is towards the luminal site and we can see already the quite a lot of cells here among the pink muscularis propria cells at this power we can actually appreciate that many of the cells have multi loads in nuclei and we also see occasional bright red spots which are likely to represent eosinophils and at this power we can readily appreciate the neutrophils here which are actually quite numerous and accompanying scatter euro novels with the bright-red granular cytoplasm so this is characteristic of acute appendicitis and these neutrophils originally of course came from the bloodstream through the process of margination adherence transmigration and chemotaxis coming into the area of injury so that they can figure Saito's the injurious agents such as bacterial organisms the last cell type that i want to show you is the macrophage so these are derived from monocytes in the blood when the exits the bloodstream and get into tissues they are called macrophages and these cells are often quite large here thus actually numerous macrophages all over the place here this happens to be a brain in fact and they are eating up material which comprises a lot of fatty material lipid from myelin sheaths so these are macrophages they are usually large cells you can compare them in size to the red blood cells here in the background they have low nuclear cytoplasmic ratios and abundant cytoplasm sometimes the nucleus can be a little bit bean shaped that's not so obvious in this particular case but occasionally you can see an elongated slightly bean shaped nucleus and abundant cytoplasm here is another example of macrophages in action this is taken from the lymph node infected with TB tuberculosis and what happens is that the macrophages mean function again similar to the neutrophil is that of phagocytosis so it each update cells as well as offending organisms and sometimes when they are not able to get rid of them they coalesce and form these multinucleated giant cells you can actually see that some of the nuclei are quite elongated so this is a multinucleated giant cell composed of macrophages and if you look around you can see a lot of collections of individual macrophages here and when these activator or epithelial macrophages aggregate together to form a collection this is known as a granuloma and this is often seen in chronic inflammation particularly in some conditions like infections such as tuberculosis