3.Muscularisexternaskeletalmuscle:-intheupperesophagus&theanussmoothmuscle:证--inotherparts--isusuallyarrangedintwolayers-inner layer: circular-outerlayer:longitudinaleIunUmHE-it isthick and contain3layers inthestomachmyentericnerveplexus:myemericpiexusganglionceHs-betweentwolayersofsmoothmusclelongntudinalyetthere is an Auerbach's nerve plexusSmoot muscle celsJEJHE401.JPG
16 3. Muscularis externa v skeletal muscle: - in the upper esophagus & the anus v smooth muscle: - in other parts - is usually arranged in two layers -inner layer: circular -outer layer: longitudinal - it is thick and contain 3 layers in the stomach v myenteric nerve plexus: - between two layers of smooth muscle there is an Auerbach's nerve plexus
4.AdventitiaIstheoutmostlayerformedbylooseconnectivetissuewithtwoformsSerosa:--iscoveredwithasimplesquamousepithelium(mesothelium)-- lubricating surface and reducingfriction during movement of thedigestive tractK·Adventitia(fibrosa):--only connectivetissueblendingwiththeCTof surroundingstructures-- fixing the organ with the surroundings17
17 4. Adventitia v Is the outmost layer formed by loose connective tissue with two forms: Serosa: - is covered with a simple squamous epithelium (mesothelium) - lubricating surface and reducing friction during movement of the digestive tract Adventitia (fibrosa): - only connective tissue blending with the CT of surrounding structures - fixing the organ with the surroundings
Mesentery(bindingofdigestivetracttoabdominalwall)-MesotheliumDuct of associated gland(transportofsecretion)Mesothelium(protectivecoating;reductionofLamina propriafriction)(support)-InnercircularSubmucosa2layer (motility)(support)-Serosa (support)Muscularis mucosae(mucosal motility)Outerlongitudinalmuscle layerSubmucosalplexus(motility)LymphoidnoduleVillus (increaseof(immunedefense)mucosalsurface)Gland in the laminapropria (secretion)GlandinsubmucosalInnercircularmuscle3layer (motility)layer(secretion)Myentericplexus(controlsmusclecontraction)Schematicstructureofaportionofthedigestivetract withvariousX18componentsandtheirfunctions
18 v Schematic structure of a portion of the digestive tract with various components and their functions. 2 3 4 1
General structure of oral cavity*Mucosa*is lined with stratified squamous epithelium:-- Keratin layer is present mostly in the gingiva and hard palate-- Nonkeratinized squamous epithelium covers the soft palate,lips,cheeks, and the floor of the mouth*laminapropria:C.T.--laminapropriarestsdirectlyonbonytissue--laminapropriais continuouswithasubmucosacontaining diffuse small salivary glands
19 General structure of oral cavity v Mucosa * is lined with stratified squamous epithelium: - Keratin layer is present mostly in the gingiva and hard palate - Nonkeratinized squamous epithelium covers the soft palate, lips, cheeks, and the floor of the mouth * lamina propria: C.T. - lamina propria rests directly on bony tissue - lamina propria is continuous with a submucosa containing diffuse small salivary glands
II.TongueThe tongue is a mass of skeletalmuscle covered by a mucosa.-- The mucosa is bound tightly to the muscle bythelaminapropria,whichpenetratesbetweenthebundlesofmusclefibers.-- The muscle is arranged in bundles of manysizes;theseareseparatedbyconnectivetissueandcrosseachotherin3planes.The mucosa differs on the dorsal(upper)andventral (lower)surfaces.-Theepitheliumcoveringthedorsal surfaceispartlykeratinized.-Theventralsurfacehasathinnonkeratinizedstratifiedsquamousepithelium20skeletalmuscle
20 Ⅱ. Tongue l The tongue is a mass of skeletal muscle covered by a mucosa. - The mucosa is bound tightly to the muscle by the lamina propria, which penetrates between the bundles of muscle fibers. - The muscle is arranged in bundles of many sizes; these are separated by connective tissue and cross each other in 3 planes. l The mucosa differs on the dorsal (upper) and ventral (lower) surfaces. - The epithelium covering the dorsal surface is partly keratinized. - The ventral surface has a thin nonkeratinized stratified squamous epithelium. skeletal muscle