Ch 25 Digestive System Part 1 13 04 2010 18 18 00 4 layers mucosa innermost part o epithelium o lamina propria o muscualris mucosa smooth muscle submucosa o loose CT muscularis externa o thicker layer of smooth muscle fibers o smooth muscle layer thicker than muscularis mucosa o cells arranged in sheets o two direction serosa or adventitia o serosa serous membrane o adventitia connective tissue o outer most layer and seen in abdomen o thin layer of serous adventitia o outer layer of the gut wall when serosa not present o just CT cells and fibers Movement of GL tract Peristalsis o Propels materuals along the length of digestive tract by coordinated contractions of the circular and longitudinal layers o Forces bolus forward o Know steps kinda like ashot gun Segmentation o Primarily the circular muscle fibers o Breaks it up into segments the huge chunks of food we eat o Handles it easier Enteric Plexus of the Gut Submucosal and myenteric plexuses Part of ANS Composed of o Nerve fibers post ganglionic sympathetic and preganglionc parasympathetic axons o Neuronal ell bodies mainly post ganglionic parar sympathetic Peritoneum A serosal membrane composed of 2 layers o Visceral peritoneum seroa of the gi trct o Parietal peritoneum Menistium Fused sheets Retroperitoneam Attached to posterior abdominal and does not have a mensintary o Ascending descending colon o Pancreas o Deudonum Oral Cavity Mastication mechanical processing o Chewing with teeth tongue and the palatal surfaces Lubrication by mixing with mucous and serous salivary gland secretions Tongue teeth oral cavity Vesitbule space between teeth gums and lips Fauces space where it leaves the oral cavity o Palatoglossal arch o Palatine tonsil o Palatopharyngeal arch o Oropharynx Uvula dangling thing in back of the throat Lingual frenulum membrane of tissue on underside of tongue Frenulum of upper lip tissue connecting upper lip to gums Aids in mechanical processing and manipulation of food Sensory analysis both general sense and taste Taste o Zones look at pictures Saliva o Lubricates mouth o Solubilizes foods o Begins digestion of carbs amylase o Flushes oral surfaces and covers teeth o Contains lyozymes that helps control bacteria Salivation o Controlled by ANS Teeth Enamel one and only so don t destroy As long as ligament is in tact tooth will stay in socket but shift to be straight Esophagus Behind trachea and primary bronchi Small part of esophagus has an actual serosa o Mostly adventitia Muscularis externa turns from skeletal muscle into smooth muscle o Yet some plexuses in the upper third 13 04 2010 18 18 00 13 04 2010 18 18 00
View Full Document
Unlocking...