OBJECTIVESThischaptershouldhelpyouto:Masterthe nameof the 4 layers that form thewalls of the tubularorgans of the digestive tract and the tissuetypes found in eachlayer.VMaster the distinguishing structural features and relatedfunctions of thevarious regions of each of the tubular organs ofthedigestivetract (i.e.esophagus,stomach,small intestine,large intestine),>Know the histological structure of the oral mucosa,the tongueand taste bud.>Knowthecomponents,structureandfunctionofthegutassociatedlymphoidtissue.6
6 OBJECTIVES This chapter should help you to: Master the name of the 4 layers that form the walls of the tubular organs of the digestive tract and the tissue types found in each layer. Master the distinguishing structural features and related functions of the various regions of each of the tubular organs of the digestive tract (i.e. esophagus, stomach, small intestine, large intestine). Know the histological structure of the oral mucosa, the tongue and taste bud. Know the components, structure and function of the gut- associated lymphoid tissue
Digestive tractOutlineI.General structure of digestive tractII.TongueIII.EsophagusIV.StomachV.SmallintestineVI.Large Intestine
7 Ⅰ. General structure of digestive tract Ⅱ. Tongue Ⅲ. Esophagus Ⅳ. Stomach Ⅴ. Small intestine Ⅵ. Large Intestine Outline Digestive tract
Aphotomicrograph of a histologicalOsection ofthestomach.1.Mucosa2.Submucosa3.Muscularis4.Adventitia
8 1. Mucosa 2. Submucosa 3. Muscularis 4. Adventitia A photomicrograph of a histological section of the stomach
1. MucosaItis the innermost layerIt is most important andcomplicatedEmbodiesthe variousfunctions of different tractsegments?Can be subdivided intothree layers:a.Epitheliumb.Lamina propriac.Muscularis mucosa
9 1. Mucosa v It is the innermost layer v It is most important and complicated. v Embodies the various functions of different tract segments. v Can be subdivided into three layers: a. Epithelium b. Lamina propria c. Muscularis mucosa abc
1.Mucosaa.Epitheliumtwo types a barrier between the lumen ofthe digestive tract and the body* two types:stratifiedsquamousepi--on both ends:oral cavity,esophagus,and anal canal--withstandingabrasion(protection)·simplecolumnarepi.-on most parts:stomach,small andlargeintestine--absorptionandsecretion
1. Mucosa a. Epithelium —two types v a barrier between the lumen of the digestive tract and the body. v two types: stratified squamous epi. -on both ends: oral cavity, esophagus, and anal canal -withstanding abrasion (protection) simple columnar epi. -on most parts: stomach, small and large intestine -absorption and secretion