digestive-system消化系统

1Digestivesystem2Thefunctionofthedigestivesystemistopreparefoodforintakebybodycells.Nutrientsmustbebrokendownbymechanicalandchemicalmeansintomoleculesthataresmallenoughtobeabsorbedintothecirculation.Withincells,thenutrientsareusedforenergyandforrebuildingvitalcellcomponents.Digestiontakesplaceinthedigestivetract.3DigestivetractThehumandigestivesystemincludesmouth,pharynx,esophagus,stomach,smallintestine(duodenum,jejunumandileum),largeintestine（cecum，appendix，colonandrectum）andanus.4Mouth,oralcavityOr/o:oralcavity,oraladministrationorallanguagestomat/o:stomatitis,stomatoscopysaliva:isthewaterysubstanceproducedinthemouths.Itisproducedinandsecretedfromthesalivaryglands.Humansalivaiscomposedmostlyofwater(99.5%),butalsoincludeselectrolytes,mucus,antibacterialcompounds,andvariousenzymes.Theenzymesinthesalivabreakdownsomeofthestarchandfatinthefoodatthemolecularlevelsalivaryamylase5ToothDent/i:Dentist:amedicalprofessionalwhospecializesinthecareofteethDentalgia:toothacheodont/o:Oligodontia:theconditionofnaturallyhavingfewerthantheregularnumberofteeth,itisalsocalledhypodontiaPeriodontitis:referstoanumberofinflammatorydiseasesaffectingthetissuesthatsurroundandsupporttheteeth6tongueLingu/oLinguisticSublingualtablet:Usuallyasmall,flattabletintendedtobeinsertedbeneaththetongue,wheretheactiveingredientisabsorbeddirectlythroughtheoralmucosaandintoblood;suchatabletdissolvesverypromptly.Nitroglyerinsublingualtablet:atypeofvasodilator.Itrelaxesbloodvessels,increasingthebloodandoxygensupplytoyourheart.Thismedicineisusedtorelievechestpaincausedbyangina.7esophagusesophagusisamusculartubewhosecontractionscanpropelfoodtothestomach.eso-=inside,inwardphag/o=swallowesogastritis:Inflammationofthemucousmembraneofthestomachphagocyte:cellsthatprotectthebodybyingestingharmfulforeignparticles,bacteriaanddeadordyingcells8StomachThethreebasic/mainfunctionsofthestomacharetokillanybacteriaingested,breakdownthefoodintosmallerpiecestocreatealargersurfaceareaforeasierdigestion,andtoholdfoodandreleaseitataconstantrate.ThestomachisahighlyacidicenvironmentduetohydrochloricacidproductionandsecretionwhichproducesapHrangeusuallybetween1and2.Combinedwithdigestiveenzymes,suchanenvironmentisabletobreakdownlargemoleculestosmalleronessothattheycaneventuallybeabsorbedfromthesmallintestine.AzymogencalledpepsinogenissecretedandturnsintopepsinunderlowpHconditionsandisanecessityinproteindigestion9gastr/o:stomachgastritisgastroscopygastralgiagastrectomygastrelcosisPept/i,peps/i:digestionpepsin:anenzymeinthestomachandwhichdegradesfoodproteinsintopeptidespepticulcer:dyspepsia:hardordifficultdigestion10SmallandlargeintestineThesmallintestineisthemajorsitefordigestionandabsorptionofnutrients.Theupperpart,theduodenum,isthemostactiveindigestion.Secretionsfromtheliverandpancreasareusedfordigestionintheduodenum.Thepancreassecretesdigestiveenzymesandstomachacidneutralizingbicarbonate.Protease(enzymessecretedfromthepancreas)continuethebreakdownofproteinintosmallpeptidefragmentsandsomeaminoacids.11Theliverproducesbile,whichisstoredinthegallbladderbeforeenteringthebileductintotheduodenum.Bileemulsifiesfats,makingthemsusceptibletoenzymaticbreakdown.Bilecontainscholesterol,phospholipids,bilirubin,andamixofsalts.Thelargeintestineismadeupbythecolon,cecum,appendix,andrectum.Materialinthelargeintestineismostlyindigestibleresidueandliquid.1213enter/o:dysenteryentericcoatedtablet:Anoraldosageforminwhichatabletiscoatedwithamaterialtopreventorminimizedissolutioninthestomachbutallowdissolutioninthesmallintestine.Thistypeofformulationeitherprotectsthestomachfromapotentiallyirritatingdrug(e.g.,aspirin)orprotectsthedrug(e.g.,erythromycin)frompartialdegradationintheacidicenvironmentofthestomach.14rect/o:rectumrectaladministration:suchasbysuppository,itisinsertedintotherectumwhereitdissolvesandisabsorbedintobloodcirculation.hepat/o:liverhepatatrophia:Atrophyoftheliverhepatoma:livercancer15bile:bil/i:bilirubin:theyellowbreakdownproductofnormalhemecatabolism.Hemeisformedfromhemoglobin,aprincipalcomponentofredbloodcells.Bilirubinisexcretedinbile,anditslevelsareelevatedincertaindiseases.injaundice,whichiscausedbyhyperbilirubinemia,theskin,mucusmembraneandwhitesoftheeyesarestainedandturnyellowchol/e:cholecalciferol:VitaminD3,whichcanpromotetheabsorptionofcalcium.16melancholy:Temperamenttheory:Thetheorythatholdsthattherearefourbasictemperaments,i.e.melancholic(gloomy),choleric(irritable),sanguine(cheerful),andphlegmatic(apathetic)thataredeterminedbythepredominanceofoneofthefourhumors,i.e.blackbile,yellowbile,phlegm,andblood,respectively,tocharacterizeaperson'spsychologicalstate.