ANAT20006 Lecture Notes - Lecture 20: Duodenum, Skeletal Muscle, Somatic Nervous System
15 Aug 2018
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* occupy cavities in the body: thorax, abdomen, pelvis. * visceral systems: respiratory, digestive, urinary & male genital, endocrine & female genital. * typically tubular, with a cylindrical wall and a lumen ( space in the middle) * lumen (cid:858)light(cid:859) at the end of the tunnel. * mucosa (internal layer) may have folds that increase surface area for absorption. * muscularis (middle layer) contains smooth muscle that may produce waves of contraction (cid:858)peristalsis(cid:859) * minimises friction by secreting fluid/lubrication into the space around it. * usually derived from lining of body cavities. * can be continuous with a mesentery (anchor viscera into body wall) attaching viscera to body wall (e. g. small intestine) * wall: circular and muscular longitudinal smooth muscle around hollow viscera. * provides for motility (e. g. peristalsis pushing food through the tube) and expansion (e. g. * at critical point of storage (stretch), reflexes are initiated to cause micturition (urination) or defecation (discharge of faeces)
