The Digestive System

1The Digestive System

2DigestionMechanical (physical)ChewTearGrindMashMixChemicalCatabolic reactionsEnzymatic hydrolysisCarbohydrateProteinLipidProcessing of food (Types)

3DigestionPhasesIngestionMovementDigestionAbsorptionFurther digestion

4Digestive System OrganizationMouthOral CavityPharynxEsophagusStomachDuedenumGastrointestinal (Gl) tract (Alimentary canal)Tube within a tubeDirect link/path between organsStructuresJejenumkIleumCecumAscending colonTransverse colon

5Digestive System OrganizationDescending colonSigmoid colonRectumAnusAccessory structuresNot in tube pathOrgansTeethTongueSalivary glandsLiverGall bladderPancreas

6Anatomy of the Mouth and Throat

7Human Deciduous and Permanent Teeth

8Dorsal Surface of the Tongue

9The Major Salivary Glands

10Deglutition (swallowing)SequenceVoluntary stagePush food to back of mouthPharyngeal stageRaiseSoft palateLarynx + hyoidTongue to soft palateEsophageal stageContract pharyngeal musclesOpen esophagusStart peristalsis

11Deglutition (swallowing)ControlNervesGlossopharyngealVagusAccessoryBrain stemDeglutition center Medulla oblongataPonsDisordersDysphagiaAphagia

12EsophagusUsually collapsed (closed)3 constrictionsAortic archLeft primary bronchusDiaphragm Surrounded bySNS plexusBlood vesselsFunctionsSecrete mucousTransport food

13Peristalsis and Segmentation

14EsophagusSphinctersUpperLowerAbnormalitiesAchalasiaAtresiaHerniaBarrets esophagusEsophageal varices

15StomachUsually J shapedLeft side, anterior to the spleenMucous membraneG cells make gastrinGoblet cells make mucousGastric pit Oxyntic gland Parietal cells Make HClChief cells Zymogenic cellsPepsinGastric lipase

16Anatomy of the Stomach

17Stomach3 muscle layersObliqueCircularLongitudinalRegionsCardiac sphincterFundusAntrum (pylorus)Pyloric sphincterVascularInner surface thrown into folds RugaeContains enzymes that work best at pH 1-2

18StomachFunctionsMix foodReservoirStart digestion ofProteinNucleic acidsFatsActivates some enzymesDestroy some bacteriaMakes intrinsic factor B 12 absorptionDestroys some bacteria

AbsorbsAlcoholWaterLipophilic acidB 12

19Small IntestineExtends from pyloric sphincter ileocecal valveRegionsDuodenumJejenumIleumMovementsSegmentationPeristalsis

20Small IntestineHistologyIntestinal glands Intestinal enzymesDuodenal glands Alkaline mucousPaneth cells LysozymeMicrovilliLactealsPlica circularisSmooth muscleLymphatic tissue GALTVascular

21Small IntestineAbsorbs80% ingested waterElectrolytesVitaminsMineralsCarbonatesActive/facilitated transportMonosaccharidesProteinsDi-/tripeptidesAmino acidsLipidsMonoglyceridesFatty acidsMicellesChylomicrons

22Structure of the Villi in the Small Intestine

23Small IntestineSecretes digestive enzymesPeptidasesAmino-Di-Tri-SucrasesMaltaseLactaseSaccharidasesDi-Tri-LipaseNucleases

24Small IntestineControlRequires pancreatic enzymes & bile to complete digestion

25Large IntestineExtends from ileocecal valve to anusRegionsCecum AppendixColonAscendingTransverseDescendingRectumAnal canal

26Anatomy of the Large Intestine

27Large IntestineHistologyNo villiNo permanent circular foldsSmooth muscleTaeniae coliHaustraEpiploic appendagesOtherwise like rest of Gl tract

28Large IntestineFunctionsMechanical digestionHaustral churningPeristalsisReflexes GastroilealGastrocolicChemical digestion Bacterial digestionFerment carbohydratesProtein/amino acid breakdown AbsorbsMore waterVitamins B K Concentrate/eliminate wastes

29Feces Formation and DefecationChyme dehydrated to form fecesFeces compositionWaterInorganic saltsEpithelial cellsBacteriaByproducts of digestionDefecationPeristalsis pushes feces into rectumRectal walls stretchControlParasympatheticVoluntary

30LiverLocationR. HypochondriumEpigastric region4 LobesLeft QuadrateCaudateRightEach lobe has lobules Contains hepatocytes Surround sinusoids Feed into central vein

31LiverFunctionsMakes bileDetergent emulsifies fatsRelease promoted by:Vagus n.CCKSecretinContainsWaterBile saltsBile pigmentsElectrolytesCholesterolLecithin

32LiverDetoxifies/removesDrugsAlcoholStoresGycolgenVitamins (A, D, E, K)Fe and other mineralsCholesterolActivates vitamin DFetal RBC productionPhagocytosisMetabolizes absorbed food moleculesCarbohydratesProteinsLipids

33LiverDual blood supplyHepatic portal veinDirect input from small intestineHepatic artery/veinDirect links to heart

34The Duodenum and Related Organs

35The Organs and Positions in the Abdominal Cavity

36Structures of the Alimentary Canal