DigestiveSystemThedigestivesystemisresponsibleforbreakingdownfood,absorbingnutrientsfromthefood,andriddingthebodyofwasteproductsfromthefood.Itisroughlyninemeterslongandbeginsatthemouthandendsattheanus.Thedigestivesystemconsistsofthe:thealimentarytractmouth,pharynx,esophagus,stomach,smallandlargeintestines,rectumandanustheaccessoryorganssalivaryglands,liver,gallbladderandpancreas

Thestomachisdividedintothefundic,cardiac,body,andpyloricregions.Thestomachhasthreelayersofmuscle:anouterlongitudinallayer,amiddlecircularlayer,andaninnerobliquelayer.Theinnerliningconsistsoffourlayers:theserosa,themuscularis,thesubmucosa,andthemucosa.Themucosaisdenselypackedwithgastricglands,whichcontaincellsthatproducedigestiveenzymes,hydrochloricacid,andmucus.Thestomachisamulti-functionalorgan,itstoresfood,breaksitdownandthenemptiesitintothesmallintestine.

Thesmallintestineconsistsofthreesections.

duodenum,jejunumandileumwhichattachestothefirstportionofthelargeintestine.Functiondigestion,andabsorption.Thesmallintestinefinishestheprocessofdigestion,absorbsthenutrients,andpassestheresidueontothelargeintestine.Theliver,gallbladder,andpancreasareaccessoryorgansofthedigestivesystemthatarecloselyassociatedwiththesmallintestine.Thelargeintestineismadeupofthreeportions:theascending,transverseanddescendingcolon.Itistheportionofthedigestivesystemmostresponsibleforabsorptionofwaterfromtheindigestibleresidueoffood.Theileocecalvalveoftheileum(smallintestine)passesmaterialintothelargeintestineatthececum.Materialpassesthroughtheascending,transverse,descendingandsigmoidportionsofthecolon,andfinallyintotherectum.Fromtherectumandanus,thewasteisexpelledfromthebody.Threepairsofmajorsalivaryglands(parotid,submandibular,andsublingualglands)Salivacontainswater,mucusandenzymeamylase.FunctionsIthasacleaningactionontheteeth.Itmoistensandlubricatesfoodduringmasticationandswallowing.Itdissolvescertainmoleculessothatfoodcanbetasted.Itbeginsthechemicaldigestionofstarchesthroughtheactionofamylase,whichbreaksdownpolysaccharidesintodisaccharides.theAccessoryOrgans

Thegallbladderisapear-shapedsacthatisattachedtothevisceralsurfaceoftheliverbythecysticduct.Theprincipalfunctionofthegallbladderistoserveasastoragereservoirforbile.Bilesaltsact