DigestiveSystemThedigestivesystemisresponsibleforbreakingdownfood,absorbingnutrientsfromthefood,andriddingthebodyofwasteproductsfromthefood.Itisroughlyninemeterslongandbeginsatthemouthandendsattheanus.Thedigestivesystemconsistsofthe:thealimentarytractmouth,pharynx,esophagus,stomach,smallandlargeintestines,rectumandanustheaccessoryorganssalivaryglands,liver,gallbladderandpancreasThemouth,ororalcavity,isthefirstpartofthedigestivetract.Itisadaptedtoreceivefoodbyingestion,breakitintosmallparticlesbymastication,andmixitwithsaliva.Thelips,cheeks,andpalateformtheboundaries.Theoralcavitycontainstheteethandtongueandreceivesthesecretionsfromthesalivaryglands.Kidshave20teeth,butbythetimetheyarefullygrown,theyshouldhave32teeth(somepeopledohaveless!).Theesophagusisthesecondsteptodigestionandcloselyfollowstheoralcavity–onceswallowinghasinitiated.Thestomachisdividedintothefundic,cardiac,body,andpyloricregions.Thestomachhasthreelayersofmuscle:anouterlongitudinallayer,amiddlecircularlayer,andaninnerobliquelayer.Theinnerliningconsistsoffourlayers:theserosa,themuscularis,thesubmucosa,andthemucosa.Themucosaisdenselypackedwithgastricglands,whichcontaincellsthatproducedigestiveenzymes,hydrochloricacid,andmucus.Thestomachisamulti-functionalorgan,itstoresfood,breaksitdownandthenemptiesitintothesmallintestine.Thelargeintestineismadeupofthreeportions:theascending,transverseanddescendingcolon.Itistheportionofthedigestivesystemmostresponsibleforabsorptionofwaterfromtheindigestibleresidueoffood.Theileocecalvalveoftheileum(smallintestine)passesmaterialintothelargeintestineatthececum.Materialpassesthroughtheascending,transverse,descendingandsigmoidportionsofthecolon,andfinallyintotherectum.Fromtherectumandanus,thewasteisexpelledfromthebody.Threepairsofmajorsalivaryglands(parotid,submandibular,andsublingualglands)Salivacontainswater,mucusandenzymeamylase.FunctionsIthasacleaningactionontheteeth.Itmoistensandlubricatesfoodduringmasticationandswallowing.Itdissolvescertainmolecule