Ana Physio Digestive System

8/3/2019 Ana Physio Digestive System

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Digestive System AnatomyDigestive System Anatomy

Digestive tractDigestive tract Alimentary tract orAlimentary tract or

canalcanal

GI tractGI tract

Accessory organsAccessory organs Primarily glandsPrimarily glands

RegionsRegions Mouth or oral cavityMouth or oral cavity

PharynxPharynx

EsophagusEsophagus StomachStomach

Small intestineSmall intestine

Large intestineLarge intestine

AnusAnus


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Digestive Tract HistologyDigestive Tract Histology


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Digestive System RegulationDigestive System Regulation

Nervous regulationNervous regulation

Involves enteric nervousInvolves enteric nervous

systemsystem

Types of neurons: sensory,Types of neurons: sensory,motor, interneuronsmotor, interneurons

Coordinates peristalsisCoordinates peristalsis

and regulates localand regulates local

reflexesreflexes

Chemical regulationChemical regulation

Production of hormonesProduction of hormones

Gastrin, secretinGastrin, secretin

Production of paracrineProduction of paracrine

chemicalschemicals

HistamineHistamine

Help local reflexes in EN

SHelp local reflexes in EN

Scontrol digestivecontrol digestive

environments as pH levelsenvironments as pH levels


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Peritoneum and MesenteriesPeritoneum and Mesenteries

PeritoneumPeritoneum VisceralVisceral: Covers organs: Covers organs

ParietalParietal: Covers interior: Covers interior

surface of body wallsurface of body wall

RetroperitonealRetroperitoneal: Behind: Behindperitoneum as kidneys,peritoneum as kidneys,

pancreas, duodenumpancreas, duodenum

MesenteriesMesenteries

Routes which vessels andRoutes which vessels andnerves pass from body wall tonerves pass from body wall to

organsorgans

Greater omentumGreater omentum

Lesser omentumLesser omentum


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Oral CavityOral Cavity

Mouth or oral cavityMouth or oral cavity VestibuleVestibule: Space: Space

between lips or cheeksbetween lips or cheeksand alveolar processesand alveolar processes

Oral cavity properOral cavity proper

Lips (labia) andLips (labia) andcheekscheeks

PalatePalate: Oral cavity: Oral cavityroofroof Hard and softHard and soft

Palatine tonsilsPalatine tonsils TongueTongue: Involved in: Involved in

speech, taste,speech, taste,mastication,mastication,swallowingswallowing


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TeethTeeth

Two setsTwo sets

Primary, deciduous,Primary, deciduous,

milk: Childhoodmilk: Childhood

Permanent orPermanent or

secondary: Adult (32)secondary: Adult (32)

TypesTypes

Incisors, canine,Incisors, canine,

premolar and molarspremolar and molars


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Tooth structure:Tooth structure:


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Salivary GlandsSalivary Glands

Produce salivaProduce saliva

Prevents bacterialPrevents bacterial

infectioninfection

LubricationLubrication

Contains salivaryContains salivary

amylaseamylase

Breaks down starchBreaks down starch

Three pairsThree pairs

Parotid: LargestParotid: Largest

SubmandibularSubmandibular

Sublingual: SmallestSublingual: Smallest


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Pharynx and EsophagusPharynx and Esophagus

PharynxPharynx

NasopharynxNasopharynx

Oropharynx: TransmitsOropharynx: Transmitsfood normallyfood normally

Laryngopharynx:Laryngopharynx:

Transmits foodTransmits food

normallynormally

EsophagusEsophagus

Transports food fromTransports food frompharynx to stomachpharynx to stomach

Passes through esophagealPasses through esophageal

hiatus (opening) ofhiatus (opening) ofdiaphragm and ends atdiaphragm and ends atstomachstomach Hiatal herniaHiatal hernia

SphinctersSphincters UpperUpper

LowerLower


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Deglutition (Swallowing)Deglutition (Swallowing)

Three phasesThree phases

VoluntaryVoluntary

Bolus of food moved by tongue from oral cavity toBolus of food moved by tongue from oral cavity to

pharynxpharynx PharyngealPharyngeal

ReflexReflex: Upper esophageal sphincter relaxes, elevated: Upper esophageal sphincter relaxes, elevatedpharynx opens the esophagus, food pushed intopharynx opens the esophagus, food pushed intoesophagusesophagus

EsophagealEsophageal

ReflexReflex: Epiglottis is tipped posteriorly, larynx elevated: Epiglottis is tipped posteriorly, larynx elevatedto prevent food from passing into larynxto prevent food from passing into larynx


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Phases of DeglutitionPhases of Deglutition

(Swallowing)(Swallowing)


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FunctionsFunctions

IngestionIngestion: Introduction of food into stomach: Introduction of food into stomach MasticationMastication: Chewing: Chewing

PropulsionPropulsion

Deglutition: SwallowingDeglutition: Swallowing

Peristalsis: Moves material through digestive tractPeristalsis: Moves material through digestive tract


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Stomach Anatomy:Stomach Anatomy:

OpeningsOpenings GastroesophagealGastroesophageal::

To esophagusTo esophagus

PyloricPyloric: To: To

duodenumduodenum RegionsRegions

CardiacCardiac

FundusFundus

BodyBody

PyloricPyloric


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Stomach Histology:Stomach Histology:

LayersLayers

Serosa or visceralSerosa or visceral

peritoneum:peritoneum:

OutermostOutermost

Muscularis: ThreeMuscularis: Threelayerslayers

Outer longitudinalOuter longitudinal

Middle circularMiddle circular

Inner obliqueInner oblique SubmucosaSubmucosa

MucosaMucosa


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Stomach HistologyStomach Histology

RugaeRugae: Folds in: Folds instomach when emptystomach when empty

Gastric pitsGastric pits: Openings: Openingsfor gastric glandsfor gastric glands

Contain cellsContain cells Surface mucous: MucusSurface mucous: Mucus

Mucous neck: MucusMucous neck: Mucus

Parietal: HydrochloricParietal: Hydrochloricacid and intrinsic factoracid and intrinsic factor

Chief: PepsinogenChief: Pepsinogen

Endocrine: RegulatoryEndocrine: Regulatoryhormoneshormones


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Hydrochloric Acid ProductionHydrochloric Acid Production


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Phases of GastricPhases of Gastric

SecretionSecretion


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Movements in StomachMovements in Stomach


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Small IntestineSmall Intestine

Site of greatest amount ofSite of greatest amount ofdigestion and absorptiondigestion and absorption

DivisionsDivisions DuodenumDuodenum

JejunumJejunum

Ileum: Peyers patches orIleum: Peyers patches orlymph noduleslymph nodules

ModificationsModifications Circular folds or plicaeCircular folds or plicae

circulares, villi, lacteal,circulares, villi, lacteal,

microvillimicrovilli Cells of mucosaCells of mucosa

Absorptive, goblet, granular,Absorptive, goblet, granular,endocrineendocrine


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Small Intestine SecretionsSmall Intestine Secretions

MucusMucus Protects against digestive enzymes and stomach acidsProtects against digestive enzymes and stomach acids

Digestive enzymesDigestive enzymes Disaccharidases: Break down disaccharides toDisaccharidases: Break down disaccharides to

monosaccharidesmonosaccharides

Peptidases: Hydrolyze peptide bondsPeptidases: Hydrolyze peptide bonds

Nucleases: Break down nucleic acidsNucleases: Break down nucleic acids

Duodenal glandsDuodenal glands Stimulated by vagus nerve, secretin, chemical or tactileStimulated by vagus nerve, secretin, chemical or tactile

irritation of duodenal mucosairritation of duodenal mucosa


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Duodenum and PancreasDuodenum and Pancreas


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Duodenum Anatomy andDuodenum Anatomy and

HistologyHistology


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LiverLiver

LobesLobes MajorMajor: Left and right: Left and right

MinorMinor: Caudate and: Caudate and

quadratequadrate

DuctsDucts

Common hepaticCommon hepatic

CysticCystic

From gallbladderFrom gallbladder

Common bileCommon bile

Joins pancreatic duct atJoins pancreatic duct at

hepatopancreatic ampullahepatopancreatic ampulla


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Functions of the LiverFunctions of the Liver

Bile productionBile production Salts emulsify fats, contain pigments as bilirubinSalts emulsify fats, contain pigments as bilirubin

StorageStorage Glycogen, fat, vitamins, copper and ironGlycogen, fat, vitamins, copper and iron

Nutrient interconversionNutrient interconversion

DetoxificationDetoxification Hepatocytes remove ammonia and convert to ureaHepatocytes remove ammonia and convert to urea

PhagocytosisPhagocytosis Kupffer cells phagocytize wornKupffer cells phagocytize worn--out and dying red and white blood cells,out and dying red and white blood cells,

some bacteriasome bacteria

SynthesisSynthesis Albumins, fibrinogen, globulins, heparin, clotting factorsAlbumins, fibrinogen, globulins, heparin, clotting factors


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Blood and Bile FlowBlood and Bile Flow


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Duct SystemDuct System


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GallbladderGallbladder

Bile is stored and concentratedBile is stored and concentrated

Stimulated by cholecystokinin and vegalStimulated by cholecystokinin and vegal

stimulationstimulation Dumps into small intestineDumps into small intestine

Production of gallstones possibleProduction of gallstones possible

Drastic dieting with rapid weight lossDrastic dieting with rapid weight loss


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PancreasPancreas

AnatomyAnatomy

EndocrineEndocrine

Pancreatic islets producePancreatic islets produce

insulin and glucagoninsulin and glucagon ExocrineExocrine

Acini produce digestiveAcini produce digestive

enzymesenzymes

RegionsRegions: Head, body, tail: Head, body, tail

SecretionsSecretions

Pancreatic juice (exocrine)Pancreatic juice (exocrine) TrypsinTrypsin

ChymotrypsinChymotrypsin

CarboxypeptidaseCarboxypeptidase

Pancreatic amylasePancreatic amylase

Pancreatic lipasesPancreatic lipases

Enzymes that reduce DNAEnzymes that reduce DNAand ribonucleic acidand ribonucleic acid


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Bicarbonate Ion ProductionBicarbonate Ion Production


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Gastric hormones:Gastric hormones:


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Movement in small intestine:Movement in small intestine:

Mixing: Segmental contraction that occurs in small intestineMixing: Segmental contraction that occurs in small intestine Secretion: Lubricate, liquefy, digestSecretion: Lubricate, liquefy, digest

Digestion: Mechanical and chemicalDigestion: Mechanical and chemical

Absorption: Movement from tract into circulation or lymphAbsorption: Movement from tract into circulation or lymph

Elimination: Waste products removed from bodyElimination: Waste products removed from body


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Large Intestine:Large Intestine:

Extends from ileocecal junction to anusExtends from ileocecal junction to anus

Consists of cecum, colon, rectum, anal canalConsists of cecum, colon, rectum, anal canal

Movements sluggish (Movements sluggish (1818--24 hours24 hours))


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Large IntestineLarge Intestine

CecumCecum Blind sac, vermiform appendix attachedBlind sac, vermiform appendix attached

ColonColon

Ascending, transverse, descending, sigmoidAscending, transverse, descending, sigmoid RectumRectum

Straight muscular tubeStraight muscular tube

Anal canalAnal canal Internal anal sphincter (smooth muscle)Internal anal sphincter (smooth muscle) External anal sphincter (skeletal muscle)External anal sphincter (skeletal muscle)

Hemorrhoids: Vein enlargement or inflammationHemorrhoids: Vein enlargement or inflammation


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Secretions ofLarge IntestineSecretions ofLarge Intestine

Mucus provides protectionMucus provides protection

Parasympathetic stimulation increases rate of gobletParasympathetic stimulation increases rate of goblet

cell secretioncell secretion

PumpsPumps

Exchange of bicarbonate ions for chloride ionsExchange of bicarbonate ions for chloride ions

Exchange of sodium ions for hydrogen ionsExchange of sodium ions for hydrogen ions

Bacterial actions produce gases called flatusBacterial actions produce gases called flatus


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Histology ofLarge IntestineHistology ofLarge Intestine


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Movement in Large IntestineMovement in Large Intestine

Mass movementsMass movements Common after mealsCommon after meals

Local reflexesLocal reflexes in enteric plexusin enteric plexus

GastrocolicGastrocolic: Initiated by stomach: Initiated by stomach DuodenocolicDuodenocolic: Initiated by duodenum: Initiated by duodenum

Defecation reflexDefecation reflex Distension of the rectal wall by fecesDistension of the rectal wall by feces

DefecationDefecation Usually accompanied by voluntary movements to expel fecesUsually accompanied by voluntary movements to expel feces

through abdominal cavity pressure caused by inspirationthrough abdominal cavity pressure caused by inspiration


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Reflexes inReflexes in

Colon andColon andRectum:Rectum:

Di ti Ab tiDi ti Ab ti


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Digestion, Absorption,Digestion, Absorption,

TransportTransport

DigestionDigestion

Breakdown of food molecules for absorption intoBreakdown of food molecules for absorption into

circulationcirculation

MechanicalMechanical: Breaks large food particles to small: Breaks large food particles to small

ChemicalChemical: Breaking of covalent bonds by digestive: Breaking of covalent bonds by digestive

enzymesenzymes

AbsorptionAbsorption andand transporttransport Molecules are moved out of digestive tract and intoMolecules are moved out of digestive tract and into

circulation for distribution throughout bodycirculation for distribution throughout body


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Figure 24.20a, b

Liver HistologyLiver Histology

portal

triad


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3. Architecture of the Hepatic3. Architecture of the Hepatic

ParenchymaParenchymaThe hepatic lobuleThe hepatic lobule is the structural unit of the liver.is the structural unit of the liver.

Central vein

Portal vein

Bile duct

Sinusoids

Liver cells (Hepatocytes)

Hepatic arteryP

ortal area


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BileBile

Bile acidBile acid

PhospholipidsPhospholipids CholesterolCholesterol

BilirubinBilirubin

Waste productsWaste products

ElectrolytesElectrolytes

MucinMucin

each day around 600 ml of bile is produced


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Functions of the LiverFunctions of the Liver

Bile productionBile production Salts emulsify fats, contain pigments as bilirubinSalts emulsify fats, contain pigments as bilirubin

StorageStorage Glycogen, fat, vitamins, copper and ironGlycogen, fat, vitamins, copper and iron

Nutrient interconversionNutrient interconversion

DetoxificationDetoxification Hepatocytes remove ammonia and convert to ureaHepatocytes remove ammonia and convert to urea

PhagocytosisPhagocytosis Kupffer cells phagocytize wornKupffer cells phagocytize worn--out and dying red and white blood cells,out and dying red and white blood cells,

some bacteriasome bacteria

SynthesisSynthesis Albumins, fibrinogen, globulins, heparin, clotting factorsAlbumins, fibrinogen, globulins, heparin, clotting factors


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Exocrine PancreasExocrine PancreasEnzymesEnzymes

TrypsinogenTrypsinogen

ChymotrysinogenChymotrysinogen

CarboxypeptidasesCarboxypeptidases

ProPro--elastaseelastase

PhospholipasePhospholipase

pancreatic lipasepancreatic lipase

Pancreatic amylasePancreatic amylase


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Bicarbonate Ion ProductionBicarbonate Ion Production


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LipoproteinsLipoproteins

TypesTypes

ChylomicronsChylomicrons

Enter lymphEnter lymph

VLDLVLDL

LDLLDL

Transports cholesterolTransports cholesterol

to cellsto cells

HDLHDL Transports cholesterolTransports cholesterol

from cells to liverfrom cells to liver


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W d IW d I


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Water and Ions:Water and Ions:

WaterWater

Can move in either directionCan move in either direction

across wall of small intestineacross wall of small intestine

depending on osmoticdepending on osmotic

gradientsgradients

IonsIons

Sodium, potassium, calcium,Sodium, potassium, calcium,

magnesium, phosphate aremagnesium, phosphate are

actively transportedactively transported


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Effects of AgingEffects of Aging

Decrease in mucus layer, connective tissue,Decrease in mucus layer, connective tissue,

muscles and secretionsmuscles and secretions

Increased susceptibility to infections and toxicIncreased susceptibility to infections and toxicagentsagents

Ulcerations and cancersUlcerations and cancers

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Ana Physio Digestive System