striated(orsecretory)ducts: LMwithinalobeofglandis lined withtall columnar cells showingvertical striationsradialstriationsextendfromthebasesofthecellstothelevelofthenuclei2R
16 striated (or secretory) ducts: LM l within a lobe of gland l is lined with tall columnar cells showing vertical striations, l radial striations extend from the bases of the cells to the level of the nuclei
②striatedductEM:the striations consist of infoldings of the basal plasmamembranethis structure is characteristic of ion-transporting cells17
17 striated duct EM: l the striations consist of infoldings of the basal plasma membrane l this structure is characteristic of ion-transporting cells
?interlobularducts:islocatedintheconnectivetissueseptainitiallylinedwithsimplecolumnarepitheliumwhichgraduallybecomesstratifiedcolumnarepithelium① main duct:is linedwithnonkeratinized stratified sguamousepitheliumultimatelyempties intotheoralcavity18
18 interlobular ducts: l is located in the connective tissue septa. l initially lined with simple columnar epithelium which gradually becomes stratified columnar epithelium main duct: l is lined with nonkeratinized stratified squamous epithelium l ultimately empties into the oral cavity
D.Distinctivefeaturesof3pairsof salivaryglands1.parotidgland:structure--iscomposedexclusivelyofserouscells-intercalatedductisrelativelylong-striated duct is relatively short-theconnectivetissuecontainsmanyplasmacellsandlymphocytesfunction-itssecretionsaccountforabout25%ofthetotalsalivaryvolume
19 1. parotid gland: structure - is composed exclusively of serous cells - intercalated duct is relatively long - striated duct is relatively short - the connective tissue contains many plasma cells and lymphocytes function - its secretions account for about 25% of the total salivary volume D. Distinctive features of 3 pairs of salivary glands
2.submandibular gland:structure--itssecretoryportioncontainsboth mucousand serouscells-serouscellsarethemaincomponent(moreserousacini,lessmucousandmixedacini)--intercalatedductisrelativelyshort--striatedductisrelativelylong·functionsecretionsaccountforabout7o%ofthesalivaryvolumeserous cells
20 2. submandibular gland: structure -its secretory portion contains both mucous and serous cells -serous cells are the main component (more serous acini, less mucous and mixed acini) -intercalated duct is relatively short -striated duct is relatively long function - secretions account for about 70% of the salivary volume serous cells