text: Histology The four layers that make up the wall of the ileum are consistent with those of the gastrointestinal tract. From the inner to the outer surface, these are:
  A mucous membrane, itself formed by three different layers:
  A single layer of tall cells that line the lumen of the organ. The epithelium that forms the innermost part of the mucosa has five distinct types of cells that serve different purposes: enterocytes with microvilli, which digest and absorb nutrients; goblet cells, which secrete mucin, a substance that lubricates the wall of the organ; Paneth cells, most common in the terminal part of the ileum, are only found at the bottom of the intestinal glands and release antimicrobial substances such as alpha defensins and lysozyme; microfold cells, which take up and transport antigens from the lumen to lymphatic cells of the lamina propria; and enteroendocrine cells, which secrete hormones.
  An underlying lamina propria composed of loose connective tissue and containing germinal centers and large aggregates of lymphoid tissue called Peyer's patches, which are a distinctive feature of the ileum.
  A thin layer of smooth muscle called muscularis mucosae
  A submucosa formed by dense irregular connective tissue that carries the larger blood vessels and a nervous component called submucosal plexus, which is part of the enteric nervous system