 The submucosa ("sub-" + "mucosa") is to a mucous membrane what the subserosa ("sub-" + "serosa") is to a serous membrane.Blood vessels, lymphatic vessels, and nerves (all supplying the mucosa) will run through here.In the intestinal wall, tiny parasympathetic ganglia are scattered around forming the submucous plexus (or "Meissner's plexus") where preganglionic parasympathetic neurons synapse with postganglionic nerve fibers that supply the muscularis mucosae.