Transmission electron microscopy images of the (a) gut microbiota, (b, c) submucosal Meissner plexus, and (d) myenteric Auerbach plexus from the small intestine of 6-month-old mouse. (a) Various types of bacteria, nanoparticles, and vesicles with diverse dimensions from intestinal lumen. (b) Nerve endings of the submucosal plexus (MP—Meissner plexus) run along a lymphatic capillary (ly.cap.) between macrophages (mph), mast cells (ma), lymphocytes (L), and smooth muscle cells of muscularis mucosae (smcmm). (c) A neuron and an enteric glial cell (g) from the submucosal Meissner plexus are surrounded by telocytes (tc). (d) Nerve fibers from the myenteric Auerbach plexus (AP) in contact with an interstitial Cajal cell (ICC) between smooth muscle cells (smc) of the muscularis.