CopyrightOTheMcGraw-HiliCeParotidsalivaryglandChapter 6Mouth-PharynxTracheaSublingualsalivaryglandEsophagusGastrointestinalSubmandibularsalivaryglandPhysiologyLiverStomachDai HuaGallbladder-PancreasMedical CollegeSmallintestineColonYangzhou UniversityLargeCecumintestineRectumAnus
Chapter 6 Gastrointestinal Physiology Dai Hua Medical College Yangzhou University
Gastrointestinal PhysiologySection 1IntroductionSection2Mastication and deglutitionSection3Gastric secretionSection 4Digestion in stomachSection5Digestion in small intestinesSection 6Physiology of colonSection7Absorption
Section 1 Introduction Section 2 Mastication and deglutition Section 3 Gastric secretion Section 4 Digestion in stomach Section 5 Digestion in small intestines Section 6 Physiology of colon Section 7 Absorption Gastrointestinal Physiology
copyrightoTidisplayParotidGastrointestinalSystemsalivaryglandMouthPharynxincludes Gltractplus theTracheaSublingualaccessoryorganssalivaryglandEsophagusSubmandibularsalivaryglandMany functions in the gut are foundin specificlocations along its length.LiverMost of digestion:StomachGallbladderPancreasAccomplishedintheSmallSmallIntestine.intestineColonLargeCecumintestineAbsorption:RectumAnusOccursinthesmall intestine
Many functions in the gut are found in specific locations along its length. Gastrointestinal System Most of digestion： Accomplished in the Small Intestine. Absorption： Occurs in the small intestine. — includes GI tract plus the accessory organs
ExocrineOrganFunctionssecretionsMouthandChewingbegins;initiation ofswallowing reflexPharynxSaltandwater moistenfoodSalivaryglandsAmylasePolysaccharide-digestingenzymeEsophagusMovingfoodtostomachbyperistalticwavesMucusLubricationStomachStore,mix,andcontinuedigestionoffood;regulateemptyingofdissolvedfoodintosmall intestineHCISolubilizationoffoodparticles;kill microbes;activationofpepsinogenstopepsinsPepsinogenProtein-digestingenzymesMucusLubricateandprotectepithelialsurfacePancreasSecretion ofenzymes and bicarbonate;alsohasnondigestiveendocrinefunctionsEnzymesDigestcarbohydrates,fats,proteins,andnucleicacidsBicarbonateNeutralizeHClenteringsmall intestinefromstomachLiverBilesaltsSecretionofbile;manyothernondigestivefunctionsSolubilizewater-insolublefatsBicarbonateNeutralizeHClenteringsmallintestinefromstomachOrganicwasteproductsandtracemetalsEliminationinfecesGallbladderStoreandconcentratebilebetweenmealsSmall intestineDigestionandabsorptionofmostsubstancemixingandpropulsionofcontentsEnzymesFooddigestionSalt and waterMaintainfluidity of luminal contentsMucusLubricationLargeintestineStorageandconcentrationofundigested waterabsorptionofsaltandwater,mixingandpropulsionofManyfunctionsinthegutarefoundcontents;defecationmixingandpropulsionofcontentsinspecificlocationsalongitslengthMucusLubrication
Stomach Store, mix, and continue digestion of food; regulate emptying of dissolved food into small intestine HCl Solubilization of food particles; kill microbes; activation of pepsinogens to pepsins Pepsinogen Protein-digesting enzymes Mucus Lubricate and protect epithelial surface Pancreas Secretion of enzymes and bicarbonate; also has nondigestive endocrine functions Enzymes Digest carbohydrates, fats, proteins, and nucleic acids Bicarbonate Neutralize HCl entering small intestine from stomach Liver Bile salts Secretion of bile; many other nondigestive functions Solubilize water-insoluble fats Bicarbonate Neutralize HCl entering small intestine from stomach Organic waste products and trace metals Elimination in feces Exocrine Organ secretions Functions Mouth and Chewing begins; initiation of swallowing reflex Pharynx Salt and water moisten food Salivary glands Amylase Polysaccharide-digesting enzyme Esophagus Moving food to stomach by peristaltic waves Mucus Lubrication Small intestine Digestion and absorption of most substance mixing and propulsion of contents Enzymes Food digestion Salt and water Maintain fluidity of luminal contents Mucus Lubrication Gallbladder Store and concentrate bile between meals Large intestine Storage and concentration of undigested water, absorption of salt and water, mixing and propulsion of contents; defecation mixing and propulsion of contents Mucus Lubrication Many functions in the gut are found in specific locations along its length
FourprocessescarriedoutbytheGltractCopyrightThe McGraw-Hill Companies, Inc.Permission requiredfor reproduction or display.BloodflowHeartLiverHepaticportalveinSecretionAbsorptionMouth-AnusFoodandDigestionwaterFecesEsophagusRectumSmallintestineStomachColonMotilityFunctionsofGastrointestinalSystem
Four processes carried out by the GI tract Functions of Gastrointestinal System