submucosa organ component layer muscular coat BTO:0004838 tunica muscularis A region of muscle in many organs in the vertebrate body, adjacent to the submucosa membrane. It is responsible for gut movement such as peristalsis. muscularis propria UMLS:C0225358 uberon UBERON:0006660 tunica externa muscularis layer tunica muscularis An outer layer of smooth muscle surrounding a hollow or tubular organ as the bladder, esophagus, large intestine, small intestine, stomach, ureter, uterus, and vagina that often consists of an inner layer of circular fibers serving to narrow the lumen of the organ and an outer layer of longitudinal fibers serving to shorten its length[BTO]. currently this class conflates a generic layer of muscle and a specific layer found lining the digestive tract (the muscularis externa), typically composed of circular and longitudinal layers (although this varies) muscular layer transverse muscular fibers muscularis muscular coat typically smooth muscle, but there may be exceptions - in the upper esophagus, part of the externa is skeletal muscle, rather than smooth muscle. muscularis externa layer of muscle tissue