消化腺（全英文）课件

DigestiveSystemDigestiveGlandsComponents

digestiveglandsfoundinthewallofdigestivetract

accessorydigestiveglands: salivaryglands/pancreas/liverGeneralstructure*Parenchyma

(functionalportionofanorgan,asdistinguishedfromthesupportingtissue):

acini/glandcells duct*Stroma

(unfunctionalportionofanorgan):

capsule,CTinside.

Salivaryglands*Parotid*SubmandibularG.*SublingualG.Threetypesofacini

*serous

*mucous

*seromucousFunction:

*moisteningfood

*carbohydratedigestion*SecreteIgA

Pancreas

positionedretroperitoneallyontheposteriorwalloftheabdominalcavityatthelevelofthesecondandthirdlumbarvertebrae.

nodistinctcapsule,butiscoveredbyathinlayerofLCT

bothanexocrine&endocrinegland.

*

exocrinepart:

producespancreaticjuice

*endocrinepart:

producehormonesComponentsoftheexocrinepancreas

consistsofserousglands

acinifilledwithacidophiliczymogengranules

intercalatedductextendsintothecentreoftheacini,whichislinedbycentroacinarcells

ductsystem:intercalatedducts(lowcolumnarorcuboidal

epith.)Interlobularducts(columnarepith.)Mainpancreaticducts(tallcolumanrepth.)majorduodenalpapillaFunctionofpancreaticjuice:

*

Trypsin,chymotrypsin&carboxypeptidase

hydrolyseproteins;

*

ribonuclease&deoxyribonucleasesplitnucleicacids;

*amylasehydrolysesstarch&glycogen

*lipase

hydrolysestriglyceridesintofattyacidsandmonoglycerides

*cholesterolesterasebreaksdowncholesterolestersintocholesterolandafattyacid.ComponentsoftheEndocrine

*IslandsofLangerhansscatteredthroughouttheexocrinepancreas.

*Vascularization(manyfenestratedcap.)ismoreextensivethanthatoftheexocrineacini.*

Threedifferenttypespresent A-cells(20%):glucagonproducer B-cells(75%):insulinproducer D-cells(5%):somatostatinproducer Liver*largestgland(~2%ofbodyweightinadult).*receivesbothvenous&arterialbloodthroughtheportalV.(~75%)&hepaticA(~25%),respectively.*CTofcapsuleextendedintotheparenchyma,forming“classical〞liverloblules(basicstructureunits).*functionsasanexocrinegland(secretingbile). Structuresofliverlobules*

six-sidedprismwithacentralV.atitscentre*

delimitedbyinterlobularCT

*

portaltriads

inthecorneroflobules(portalarea)*anastomosingplatesofhepaticcells

extendedradiallyfromthecentralV.*sinusoidsformbetweenhepaticplates Portalareas*definition: aareafoundintheangleswhereadjacenthepaticlobulesmeet.*components:

CT.+portaltriad interlobularA interlobularV interlobularbileduct Sinusoids*dialatedanastomosingvenulesbetweenthehepaticplates*bloodpathway:peripherycentralv.*Kupffercells

linedinthewallofsinusoids*EM:significantgapsnumerousfenestration

incompletebasallaminaHepatocytes*makeupabout80%ofthecellsintheliver.*typicallylargepolyhedralcellswithlargeroundcentrallylocatednuclei.

*abundanceoforganellesrelatedtothefunctions

Mitochondria:energyproviding

RER:proteinsynthesis

SER:bileformation/metabolismoflipidsandhormones/detoxification.

Lysosome:replacementanddefence

Microbody:detoxification.

Inclusions:glcogenparticles,lipiddropletsandpigments.Hepatocytefunction*Producebile*mediatecarbohydratereserves

glycogenisdegradedtoglucoseunder regulationofhormones*Bloodlipidmetabolism*Synthesisofplasmaproteins

albumin:majorplasmaprotein

fibrinogen thrombin clottingfactorIIIBileCanaliculiDefinition: tubularspacelimitedbyplasmamembraneoftwoadjacenthepatopcytes.Structure:LM:network-likestructuresareseenbysilverimpregnationEM:

*plasmamembraneofadjacenthepatocytes formthewallofbilecanaliculi

*tightjunctionsformsealsBliecanaliculistainedbysilverimpregnationPerisinusoidalsapce(spaceofDisse)

aspacebetweentheendothelium&hepatocyte

be

visibleunderEM

occupiedbynumerous

microvilliofhepatocytes

filledwithplasma

fat-storingcells(storingfat&vitaminA)

asiteforexchangebetweentheblood&

hepatocytes.*celljunctionsurface*

Perisinusoidalsurface:facetoperisinusoidalspace*

bilecanalicularsurface:faceintothebilecanaliculusInterlobuleA.&V.Threetypesoffunctionalsurfaceinhepatocyte

HepaticBloodSupply

PortalV→interlobularV→→ HepaticA→interlobularA→→sublobularVsinusoids

centralVhepaticVInferiorvenacava(75%)(25%)Bilecanaliculi→periperalbileductules(Hering’s)

interlobularbileductLeft&righthepaticductsCommonhepaticductCommonbileductDuodenumpapilla

CysticductGallbladderBiliaryPassagesClassificationofLobulesClassiclobule:

Ahexagonalstructurewiththecentralveinatitscenter;atthesixcornersofthelubulearehepatictriads