This image (HA29) shows a Peyer's patch in the ileum at low magnification. A Peyer's patch includes a cluster of lymphoid nodules (n) and all of the surrounding mucosa and submucosa.The muscularis externa (me) is outermost. A number of villi (v) and crypts (c) can be seen. Two cell types are found in the epithelium (arrows) covering the nodules. These are absorptive cells and M cells.. The M cells are antigen presenting cells.