Mathematics. the identity element of a group in which the operation is addition. (of a function, especially of a function of a complex variable) a point at which a given function, usually a function of a complex variable, has the value zero; a root.
Mucosa buccalis. The inner lining of the cheeks and lips, which is an anatomic region that includes all the mucous membrane lining of the inner surface of the cheeks and lips, from the line of contact of the opposing lips to the line of attachment of mucosa to the alveolar ridges and pterygomandibular raphe, which occupies an area of 50â60 cm2.
The muscularis mucosae is a thin layer of smooth muscle at the boundary between mucosa and submucosa. It occurs throughout the GI tract from esophagus to rectum. It is thickest in esophagus, where it consists of relatively conspicuous bundles of longitudinal muscle fibers.roceeding from the inside (i.e., ab luminally from the lumen): 1  Mucosa -- innermost layer (closest to the lumen), the soft, squishy lining of the tract, consisting of epithelium, lamina propria, and muscularis mucosae. 2  Submucosa -- connective tissue supporting (outside, deep to) the mucosa.