蘿卜家園Chapter5DigestionandAbsorption消化與吸收

Chapter5DigestionandAbsorption

(消化與吸收)1Digestion(消化):Thebreak-downprocesswherebythestructurallycomplexfoodstuffsofthedietareconvertedintosmallerabsorbableunitsbytheenzymesproducedwithinthedigestivesystem(食物在消化道內(nèi)被分解為小分子物質(zhì)的過(guò)程)

Mechanicaldigestion(機(jī)械性消化)Chemicaldigestion(化學(xué)性消化)2

Absorption(吸收):Theprocessthatthesmallerabsorbableunitsofdigestiongetacrossthealimentarytractmucosaandcomeintobloodorlymph.(食物經(jīng)消化后通過(guò)消化道粘膜進(jìn)入血液或淋巴的過(guò)程)3Section1StructureofDigestiveTract

(消化管的結(jié)構(gòu))Intracellulardigestion(胞內(nèi)消化)Extracellulardigestion(胞外消化)

41.HumanDigestiveTract(人的消化管)

粘膜層：上皮上皮下層粘膜肌層粘膜下層:C.T組織結(jié)構(gòu)(Submucouslayer)環(huán)行肌胃部是三層

Smoothmuscle內(nèi)斜,中環(huán),外縱縱行肌漿膜:C.T

(Serousmembrane)

(Tissuestructure)(Mucouslayer)52.TheInnervationofDigestiveTract

(消化管的神經(jīng)支配)

ExtrinsicNS&IntrinsicNS

CNS肌間N叢粘膜下N叢R平滑肌分泌細(xì)胞內(nèi)分泌細(xì)胞交.副交N交.副交N局部6Sympatheticnerve(交感N):

Thesubdivisionoftheautonomicnervoussystemthatdominatesin“fight-or-flight”emergencyorstressfulsituationsandperparesthebodyforstrenuousphysicalactivity.(源自T5~T10&L1~L2在腹神經(jīng)節(jié)和腸系膜上下N節(jié)換元)7交感NNE胃腸平滑肌血管平滑肌運(yùn)動(dòng)及分泌內(nèi)在N元8副：延髓背核疑核

迷走N盆NS2-4運(yùn)動(dòng)及分泌內(nèi)在N元胃腸平滑肌血管平滑肌9Myentericplexus(肌間N叢)Submucousplexus(粘膜下N叢)Intrinsicplexus(內(nèi)在N叢)：

包括感覺(jué)、中間、運(yùn)動(dòng)神經(jīng)元構(gòu)成一個(gè)完整且相對(duì)獨(dú)立的整合系統(tǒng)胃腸運(yùn)動(dòng)及分泌10Section2TheMovementandRegulationofDigestiveTract

(消化管的運(yùn)動(dòng)及調(diào)節(jié))

Themovementofdigestivetract(消化道的運(yùn)動(dòng)):

Mastication(咀嚼)Deglutition(吞咽) Gastrointestinalmovement(胃腸運(yùn)動(dòng))11Reflex(反射):Anyresponsethatoccursautomaticallywithoutconsciouseffort.(在NS的參與下對(duì)刺激的規(guī)律性應(yīng)答)

Reflexarc(反射弧):Thecomponentsofareflexarcincludeareceptor,afferentpathway,integratingcenter,efferentpathway,andeffector.(感受器傳入NN中樞傳出N效應(yīng)器)121.Gastricmovement(胃的運(yùn)動(dòng))(1)Receptiverelaxation(胃的容受性舒張)Definition:

foodstimulatethereceptorsinpharynxandesophagus,throughvagusnervearouserelaxationoffundusandbodyofstomachmuscle.(食物刺激咽、食管等處感受器經(jīng)迷走神經(jīng)反射性引起胃底、胃體肌舒張)

significance肽類(lèi)纖維？13(2)Toniccontraction(緊張性收縮)(3)Peristalsis(蠕動(dòng))GastricBER(胃的基本電節(jié)律):Itstemsfromlongitudinalmuscleofgreatercurvature,3~5timesperminutes,amplitudeisabout5~15mv.(起源于胃大彎的縱行肌層，每分鐘3~5次，振幅約5~15mv)14

Function

ofperistalsis(蠕動(dòng))

：①Leadtoamplemixingofchymeanddigestivejuice,thisisfacilitatedforchemicaldigestion.使食糜與消化液充分混合，利于化學(xué)性消化②Millfood(mechanicaldigestion)磨碎食物(即機(jī)械性消化)③Pushchyme推進(jìn)食糜152.GastricEmptyingandItsRegulation

(胃的排空及其控制)Definition:Theprocessthatfoodenterintoduodenumfromstomach.(食物由胃排入12指腸的過(guò)程)

(1)胃排空(gastricemptying)

16Emptyingvelocity(排空速度)：Sugar>protein>fat;Sparse,thin,isosmoticquick(稀、細(xì)、等滲──快)(反之則慢)17(2)Regulationofgastricemptying

(胃排空的調(diào)控)

Entogastricfactorsaccelerateemptying(胃內(nèi)因素促進(jìn)排空)：①Entogastricfood（Nr）(胃內(nèi)食物)②Gastrin（Hr）(胃泌素)

18Factorsofduodenuminhibitemptying(12脂腸因素抑制排空)：

①Gastrointestinalreflex（Nr）(腸胃反射)②Enterogastrone（Hr）(腸抑胃素)19Emptyingprocess

(排空過(guò)程)：

Entogastricfood(胃內(nèi)食物)

emptyingstopped(排空停止)motilityofthestomach(胃運(yùn)動(dòng))↑

胃運(yùn)動(dòng)↓幽門(mén)括約肌舒張幽門(mén)括約肌收縮胃內(nèi)壓>12指腸內(nèi)壓N(腸胃反射)H(腸抑胃素)Nr.Hr排空腸內(nèi)胃酸被中和食物被消化吸收203.Themovementsofsmallintestine

(小腸的運(yùn)動(dòng))(1)Toniccontraction(緊張性收縮)

Functions：

①M(fèi)aintainbasicpressure(維持基礎(chǔ)壓力)②Thebasisofmovements(是腸運(yùn)動(dòng)的基礎(chǔ))③Fixandkeepshapeofsmallintestine(維持小腸的位置形狀)21(2)Segmentationcontraction

(分節(jié)運(yùn)動(dòng))

22Functions：①I(mǎi)tcanleadtoamplemixingofchymeanddigestivejuice,thisisfacilitatedforchemicaldigestion.(使食糜與消化液充分混合，利于化學(xué)性消化)②Itcanaccelerateclosecontactofchymeandintestinalwall,thisisfacilitatedforabsorption.(使食糜與腸壁緊密接觸，利于吸收)23③Itcanpressintestinalwall,acceleratebloodandlymphcircumfluence.(擠壓腸壁而促進(jìn)血液、淋巴回流)(3)Peristalsis(蠕動(dòng))Peristalsisfunction:

pushchyme(推進(jìn)食糜)24(4)Largeintestinalmovementanddefecation

(大腸運(yùn)動(dòng)和排便)

①Themovement

formsoflargeintestine

(大腸運(yùn)動(dòng)形式)

1)袋狀往返運(yùn)動(dòng)2)分節(jié)或多袋推進(jìn)運(yùn)動(dòng)3)Peristalsis(蠕動(dòng))(massperistalsis,集團(tuán)蠕動(dòng))

25

Brainstem,cerebralcortex(腦干、大腦皮層)S2-S4直腸牽張R

盆N陰部腹肌膈肌糞糞降結(jié)腸乙狀結(jié)腸收內(nèi)括約肌松馳②Defecationreflex(排便反射)外括約肌松馳26(5)Regulationofdigestivetract

(消化管運(yùn)動(dòng)的調(diào)節(jié))①Electricalactivity(電活動(dòng))BERAP②Nervefactors(神經(jīng)因素)

Sympatheticnerve(-)gastrointestinalmovement

交感N(-)胃腸運(yùn)動(dòng)

Vagusnerve(+)gastrointestinalmovement迷走N(+)胃腸運(yùn)動(dòng)27Intraparietalnerveplexus(壁內(nèi)N叢):

Regulatinggastrointestinalmovement(調(diào)節(jié)胃腸運(yùn)動(dòng))Cerebralcortex(大腦皮層):Interestforfoodeffectsdigestion.Psychogenicenterorrhea(對(duì)食物的好惡對(duì)消化的影響精神性腹瀉)283.Humoralfactors(體液因素):

Gastrointestinalhormone(主胃腸激素):

Motilin(胃動(dòng)素)Gastrin(胃泌素)

抑胃肽NESecretin(促胰液素)movementmovement29Section3TheSecretionandRegulationofDigestiveJuice(消化液的分泌及調(diào)節(jié))1.Thesecretionofsaliva(唾液的分泌)30(1)Thecharacters、componentsandfunctionsofsaliva(唾液性質(zhì)與成分與作用)

Moisten,dissolvefood(濕潤(rùn)、溶解食物)clean,protectmouthcavity(清潔、保護(hù)口腔)lubricate,hydrolyzeamylum,killbacteria

(潤(rùn)滑水解淀粉殺菌)31(2)

Theregulationofsalivarysecretion(唾液分泌的調(diào)節(jié))Doubleexcitationeffectofsympathesisnerveandparasympathesisnerve(交感與副交感雙重興奮作用)

Conditionedreflex(條件反射)\ Unconditionedreflex(非條件反射)322.Gastricsecretion(胃液的分泌)

(1)Characters,componentsandfunctions

ofgastricjuice(胃液的性質(zhì)、成分和作用)

無(wú)色透明，pH0.9～1.533

①Pepsinogen(胃蛋白酶原)

–chiefcellsecretion

(主細(xì)胞分泌)

pepsin胃蛋白酶

HClprotein月示和胨+pH234

②MucusandHCO3-(粘液與碳酸氫鹽)胃粘液-碳酸氫鹽屏障表面上皮細(xì)胞粘液頸細(xì)胞賁門(mén)腺glycoprotein35

Functions：Lubricate,protectgastricmucosa,gastricmucosalbarrier;recoveringgastricmucosalepithelia.(潤(rùn)滑、保護(hù)胃粘膜胃粘液屏障，胃粘膜屏障;胃粘膜上皮的更新)36③Thesecretionofhydrochloricacid-parietal

cell(鹽酸壁細(xì)胞分泌)Thefunctionsofhydrochloricacid

(鹽酸作用):37

1)ActivatepepsinogenandsupplysuitablePHtopepsin(激活胃蛋白酶原并給胃蛋白酶提供活動(dòng)所需的酸性pH)2)Killbacteria(殺菌)3)Acceleratedenaturationofprotein,andfacilitatedtodigestion

(使蛋白質(zhì)變性易于消化)384)Acceleratethesecretionofpancreaticjuice、bile、smallintestinaljuice.

(促進(jìn)胰液、膽汁、小腸液分泌)5)Acceleratetheabsorptionofsmallintestinaltoironandcalcium.(促進(jìn)小腸對(duì)鐵、鈣的吸收)39Function：1)ProtectB12doesn’thydrolyzedbydigestiveenzyme(保護(hù)B12不被消化酶水解)2)AcceleratetheabsorptionofileummucosatoB12.(促進(jìn)B12經(jīng)回腸粘膜吸收)④Intrinsicfactor(內(nèi)因子)

40(2)Theregulationofgastricjuicesecretion

(胃液分泌的調(diào)節(jié))Shamfeeding(假飼)

Fig5-1841①Gastricjuicesecretionofcephalicphase

(頭期胃液分泌)

Thefoodstimulatescephalicreceptorcausegastricjuicesecretion.(食物刺激頭部感受器引起的胃液分泌)42CephalicR

nervecentergastricglandsecretegastricjuice

Gcell----→gastrin（胃泌素）↑c(diǎn)haracters:

quantityandacidityishigh,digestiveenzymeishigher.(量、酸度很高，消化力(酶)尤高)(頭部R)(中樞)(胃腺分泌胃液)43②Gastricjuicesecretionofgastricphase(胃期胃液分泌)

Foodstimulatesstomachcausethegastricjuicesecretion.

(食物刺激胃引起的胃液分泌）

44

胃底胃體機(jī)械刺激──→中樞──→胃腺分泌胃液↑食物胃幽門(mén)部機(jī)械刺激──→壁內(nèi)神經(jīng)叢胃幽門(mén)部化學(xué)刺激─→幽門(mén)部G細(xì)胞─→胃泌素↑

Characters:

Acidityisquitehigh,digestiveenzymeisweakerthancephalicphase.

(酸度高，消化力(酶)比頭期的弱)ⅩⅩ45③Gastricjuicesecretionofintestinalphase(腸期胃液分泌)

Thefoodstimulatesintestinecausethegastricsecretion

（食物刺激腸引起的胃液分泌）46

Smallintestine

(小腸)

foodGastrin，entero-oxyntin（胃泌素、腸泌酸素)Gastricglandsecretegastricjuice(胃腺分泌胃液)characters:fewquantity.(量少)47④Inhibitoryregulationofgastricsecretion

(胃液分泌的抑制性調(diào)節(jié))

1)HCl胃竇粘膜G細(xì)胞

mucosalDcellsomatostain↑

intestinalmucosaScell

secretin↑

duodenalampullabulbomycin

↑

胃泌胃(粘膜D細(xì)胞)(生長(zhǎng)抑素)(腸粘膜S細(xì)胞)(促胰液素)(12指腸球部)(球抑胃素)482)

Fatsmallintestineenterogasterone

mucosa

(腸抑胃素)(小腸粘膜)

gastricjuice

(胃液)

gastricmovement

(胃運(yùn)動(dòng))

493)Hypertonicsolutionsmallintestinemucosa

(高張溶液)(小腸粘膜)

osmoticpressureR↑inhibitiveH↑(小腸滲透壓R)(抑制性H)胃液504)PGEVagusnerve,gastrin(迷走N、胃泌素)gastricwallreleasePGE

(胃壁釋放PGE)

胃液515)Theeffectsofdifferentfoodongastricjuice

secretion(不同食物對(duì)胃液分泌的作用)Protein>sugar>fat(蛋白質(zhì)>糖類(lèi)>脂肪)Corn,sweetpotato,alcohol,coffee(玉米面,白薯,紅薯,酒精,咖啡)523.Thesecretionofpancreaticjuice

(胰液的分泌)

HCO3-H2OEnzymesSmallvesselcell(小導(dǎo)管細(xì)胞)Acinarcell(腺泡細(xì)胞)Pancreas(胰腺)53(1)Thecharacters、componentsandfunctions

ofpancreaticjuice

(胰液的性質(zhì)成分和作用)

CharactersAchromiaandtasteless(無(wú)色無(wú)臭)pH7.8-8.454Componentsandfunctions

①Waterdilutefood(稀釋食物)55②Sodiumbicarbonate(碳酸氫鹽)

counteractacidandsupplysuitablepHforactivityofdigestiveenzymeinsmallintestine(中和胃酸并提供小腸內(nèi)消化酶活動(dòng)所需的最適pH)pH7-8HHCO3-+56Organiccomponents:digestiveenzymes

(有機(jī)成分主要是各種消化酶)：①Pancreaticamylase(胰淀粉酶)maltsugar,glucose

(麥芽糖、葡萄糖)淀粉57②Lipase(胰脂肪酶)Fattyacid,glyceride,glycerin

(脂肪酸、甘油一酯、甘油)輔脂酶脂肪58③

胰蛋白酶

(trypsin)糜蛋白酶

(chymotrypsin)

(多肽、AA)

腸致活蛋白質(zhì)和胨酸Trypsinogen(胰蛋白酶原)Chymotrypsinogen(糜蛋白酶原)+月示59④Others

Carboxypeptidase

羧基肽酶

Deoxyribonuclease

(脫氧)核糖核酸酶

60(2)Theregulationofpancreaticjuice

(胰液分泌的調(diào)節(jié))

NrEnzymeisquiteabundant,H2OandHCO3-arefew.

(酶很豐富，但H2O、HCO3-很少)Hr①Secretin(促胰液素)

Enzymeisquitefew,H2OandHCO3-areabundant.(H2O、HCO3-很豐富，但酶很少)61②Cholecystokinin(膽囊收縮素)

Enzymeisabundant,quantityisslightlyincreased.(酶多，量增加少許)③Gastrin(胃泌素)

Enzymeisabundant,quantityisslightlyincreased.(酶多，量增加少許)62

Secretin(促胰液素)Food(刺激強(qiáng)度：鹽酸>蛋白分解產(chǎn)物>脂酸鈉)

smallintestinesecretin(促胰液素)↑mucosaScell(小腸粘膜S細(xì)胞)

水鹽胰腺小導(dǎo)管細(xì)胞

63

Cholecystokinin,CCK(膽囊收縮素)Food(蛋白分解產(chǎn)物>脂酸鈉>鹽酸>脂肪)smallintestineCCK↑mucosaIcell(小腸粘膜I細(xì)胞)cholecystcontractionpancreaticacinarcell

排膽汁酶(膽囊收縮)

(胰腺腺泡細(xì)胞)644.TheSecretionandRegulationofOtherDigestiveJuice(其它消化液的分泌及調(diào)節(jié))Bile(膽汁):

VagusN(迷走N)G.,S.,CCK(+)Smallintestinaljuice(小腸液):

VagusNG.,S.,CCK,VIP65

intestinalmucosa(腸粘膜)Chyme(食糜)localreflex(局部反射)

intesti