I want to talk about the histology slide of a human appendix, stained with the standard dye. The most obvious feature here is the heavy concentration of purple, "grainy" looking areas, those are the lymphoid nodules. Since the appendix is basically a lymphoid organ, you can see those follicles packed into the submucosa, which is why it looks so dense and dark in those spots. Along the top edge, you can see the mucosa layer. It’s lined with simple columnar epithelium and features several crypts of Lieberkühn (those tube-like structures pointing downward). Unlike the small intestine, there aren't any villi here; the surface is much flatter. You can also spot some lighter, circular spots within the lining, which are the goblet cells that secrete mucus. The way the lymphoid tissue almost "invades" the surrounding layers is the big giveaway that this is the appendix and not just a random section of the colon.
I want to talk about the histology slide of a human appendix, stained with the standard dye. The most obvious feature here is the heavy concentration of purple, "grainy" looking areas, those are the lymphoid nodules. Since the appendix is basically a lymphoid organ, you can see those follicles packed into the submucosa, which is why it looks so dense and dark in those spots. Along the top edge, you can see the mucosa layer. It’s lined with simple columnar epithelium and features several crypts of Lieberkühn (those tube-like structures pointing downward). Unlike the small intestine, there aren't any villi here; the surface is much flatter. You can also spot some lighter, circular spots within the lining, which are the goblet cells that secrete mucus. The way the lymphoid tissue almost "invades" the surrounding layers is the big giveaway that this is the appendix and not just a random section of the colon.