ReviewitheistructureiandifunctioniofitheiGIitracti-i
iiiiiiiii☑️
iiii
GIitractiorgansi-i
iiiiiiiii☑️
iiiimouth
pharynx
esophagus
stomach
smalliintestine
largeiintestine
accessoryiorgansi-i
iiiiiiiii☑️
iiiiteeth
tongue
gallbladder
salivaryiglands
liver
pancreas
organsiusediforimechanicaliprocessingiofifoodi-i
iiiiiiiii☑️
iiiioralicavity
teeth
tongue
salivaryiglandsi-i
iiiiiiiii☑️
iiii-containiamylaseienzymeitoibreakidownicarbs
-bolusiformation
pharynxi-i
iiiiiiiii☑️
iiiimuscularipropulsioniofifoodiintoiesophagus
esophagusi-i
iiiiiiiii☑️
iiiipassagewayithatiusesiperistalsisitoimoveifooditowarditheistomach
stomachi-i
iiiiiiiii☑️
iiii-chemicalidigestioniviaiacidiandipepsini(digestiproteinsiintoiaminoiacids)
-mechanicalidigestioniviaimuscularicontractions
-3ilayersiofismoothimuscle
Whatirole(s)idoesitheiliveriserve?i-i
iiiiiiiii☑️
iiiiestimateditoihaveioveri200ifunctions
-producesibile
-storesivitaminsiandimineralsiandiconvertsithemitoibeiuseableibyitheibody
-metabolizesihormonesiandidrugs
-synthesizesiproteins,iglucose,iandiclottingifactors
-changesiammoniaitoiurea
-convertsifattyiacidsitoiketones
,-canistoreilargeiamountsiofiglucoseiasiglycogen
-canisynthesizeiglucoseifromiaminoiacids,iglycerol,iandilacticiacididuringitimesiofifastingioriincreasedid
emand
-caniconvertiexcessicarbohydratesitoitriglyceridesiforistorageiiniadiposeitissue
-isiaimajorisiteiforiproteinisynthesisiandidegradation.
liveri-i
iiiiiiiii☑️
iiii-bileisynthesis
-storeiandireleaseinutrientsi(glycogeniandilipids)
-maintainsiconcentrationsiofiglucose,iaminoiacids,iandifattyiacidsiiniblood
-cholesterolisynthesis
-inter-conversioniofinutrientitypesiwhenineeded
gallbladderi-i
iiiiiiiii☑️
iiii-storesibile
-wheniaifattyimealiisiconsumed,itheigallbladderiisisignalediviaihormonesitoicontracti
-wheniiticontractsiitiemptiesibileiintoismalliintestineitoiaidiinifatidigestion
pancreasi-i
iiiiiiiii☑️
iiiiexocrineifunctions:
-producesipancreaticijuiceiwithienzymesiandialkalineibufferi(neutralizesistomachiaciditoinotiharmismall
iintestine)itoiaidiinidigestioniinismalliintestinei(proteaseitoibreakidowniproteins,ilipaseiforifats,iamylaseif
oristarch)
endocrineifunctions:
-secretesihormonesi(insuliniandiglucagon)itoiregulateibloodiglucoseilevels
-insulinidropsibloodiglucose
-glucagoniraisesibloodiglucoseiduringifasting
smalliintestinei-i
iiiiiiiii☑️
iiii-chemicalidigestioniintoimacronutrients
-absorptioniofinutrients,ivitamins,iwater,iions
-needsilargeisurfaceiareaitoiabsorbiallinutrients
largeiintestinei-i
iiiiiiiii☑️
iiii-mainlyiabsorptioniofiwater
-microbiomeihelpsiproduceisomeivitaminsitoibeiabsorbedi(vitaminiK)
-eliminationiofiindigestibleifood
-fecesiisieliminatediviaiperistalsis
4ilayersiofitheiGIiwalli-i
iiiiiiiii☑️
iiiimucosalilayer
submucosalilayer
muscularisiexterna
serosalilayer
mucosalilayeri-i
iiiiiiiii☑️
iiii-1iofi4ilayersiofitheiGIiwall
-Producesimucusithatilubricatesiandiprotectsitheiinnerisurfaceiofitheialimentaryicanal
-Secretesidigestiveienzymesiandisubstancesithatibreakidownifood
-Absorbsitheibreakdowniproductsiofidigestion
-Maintainsiaibarrieritoipreventitheientryiofinoxiousisubstancesiandipathogeniciorganisms
, submucosalilayeri-i
iiiiiiiii☑️
iiii-1iofi4ilayersiofitheiGIiwall
-bloodivessels,inerves,iandistructuresitoisecreteidigestiveienzymes
muscularisiexternai-i
iiiiiiiii☑️
iiii-1iofi4ilayersiofitheiGIiwall
-innerilayerioficircularlyiarrangedismoothimuscleicellsiandianiouterilayeriofilongitudinallyiarrangedism
oothimuscleilayers
-TheseilayersihelpimoveitheicontentsithroughitheiGIitract
serosalilayeri-i
iiiiiiiii☑️
iiii-1iofi4ilayersiofitheiGIiwall
-serousimembrane
-outermostilayeriofiorgans,icalleditheivisceraliperitoneum
mesenteryi-i
iiiiiiiii☑️
iiii-
doubleilayeriofiperitoneumithatienclosesiaiportioniorialliofioneiofitheiabdominalivisceraiandiattachesiitito
itheiabdominaliwall
-hasibloodivessels,inerves,iandilymphaticivesselsithatisupplyitheiintestinaliwall
-holdsitheiorgansiiniplaceiandistoresifat
omentumi-i
iiiiiiiii☑️
iiii-double-
layerediextensioniorifoldiofiperitoneumithatihangsidownifromitheistomachitoiadjacentiorgansiinitheiabdo
minalicavity
-greateriomentumiandilesseriomentum
greateriomentumi-i
iiiiiiiii☑️
iiii-containsifatiandihasiailotiofimobilityitoifollowitheimovementsiofitheiintestines
-connectsitoitheistomachiandicoversitheitransverseicolonianditheifoldsiofitheiintestine
-caniformiadhesionsi(fibrousiscaritissue)iadjacentitoiinflamediorgans,isuchiasitheiappendix
-cushionsitheiabdominaliorgansiagainstiinjuryiandiprovidesiinsulationiagainstitheilossiofibodyiheat
lesseriomentumi-i
iiiiiiiii☑️
iiii-lesseriomentumiextendsibetweenitheiliveriandilessericurvatureiofitheistomach
rhythmicimovementsi-i
iiiiiiiii☑️
iiii-intermittenticontractionsithatihelpitoimixiandimoveifoodialong
-foundiinitheiesophagus,iantrumiofitheistomach,iandismalliintestine.
tonicimovementsi-i
iiiiiiiii☑️
iiii-haveiaiconstantilevelioficontractionioritoneiwithoutiregulariperiodsiofirelaxation
-locatediinitheiloweriesophagus,itheiupperiregioniofitheistomach,itheiileocecalivalve,ianditheiinternalian
alisphincter.
entericinervousisystemi-i
iiiiiiiii☑️
iiii-madeiupibyimyentericiandisubmucosaliplexusesilocatediinitheiwalliofitheiGIitract
-Theseitwoiplexusesiareinetworksiofinerveifibersiandiganglionicellibodies
-Interneuronsiconnectiafferentisensoryifibers,iefferentimotorineurons,iandisecretoryicellsitoiformireflexi
circuits.