Gross Anatomy of the Kidney - OpenStax CNX

1 Op enStax-CNXmo dule:m464291 GrossAnatomyoftheKidney OpenStaxCollegeThisworkispro ducedbyOp AbstractBytheendofthissection,youwillb eableto: Describ etheexternalstructureofthekidney,includi ngitslo cation,supp ortstructures,andcovering Identifythema jorinternaldivisionsandstructuresoftheki dney Identifythema jorblo o dvesselsasso ciatedwiththekidneyandtracethepathofblo o dthroughthekidney Compareandcontrastthecorticalandjuxtamed ullarynephrons Namestructuresfoundinthecortexandmedulla Describ ethephysiologicalcharacteristicsofthecor texandmedullaThekidneyslieoneithersideof thespineintheretrop eritonealspaceb etweentheparietalp eritoneumandthep osteriorab dominalwall,wellprotectedbymuscle,fat, st, ,receivingab out25p ercentofthecardiacoutputatrest.

2 :Therehaveneverb eensu cientkidneydonationstoprovideakidneytoea chp outtheTED(Technology,En-tertainment,Desi gn) , printed. Thesuccessfulutilizationofthistech-nolog yisstillseveralyearsinthefuture,butimagi neatimewhenyoucanprintareplacementorgano rtissueondemand. :Jun19,20133:26pm-0500 ://op enStax-CNXmo dule:m4642921 ExternalAnatomyTheleftkidneyislo catedatab outtheT12toL3vertebrae, erp ortionsofthekidneysaresomewhatprotectedb ytheeleventhandtwelfthribs(Figure1(Kidne ys)).Eachkidneyweighsab out125 175ginmalesand115 out11 14cminlength,6cmwide,and4cmthick,andared irectlycoveredbya brouscapsulecomp osedofdense,irregularconnectivetissuetha thelpstoholdtheirshap ck-absorbinglayerofadip osetissuecalledtherenalfatpad, ,toalesserextent,theoverlyingp eritoneumserveto rmlyanchorthekidneystothep osteriorab dominalwallinaretrop eritonealp :Thekidneysareslightlyprotectedbytheribs andaresurroundedbyfatforprotection(notsh own).

3 Onthesup eriorasp uencesrenalfunctionthroughthepro ductionofthehormonealdosteronetostimulat eso enStax-CNXmo dule:m4642932 InternalAnatomyAfrontalsectionthroughthe kidneyrevealsanouterregioncalledtherenal cortexandaninnerregioncalledthemedulla(F igure2(LeftKidney)).Therenalcolumnsareco nnectivetissueextensionsthatradiatedownw ardfromthecortexthroughthemedullatosepar atethemostcharacteristicfeaturesofthemed ulla, 8lob esandprovideasupp :vessels,nerves,lymphatics, elvis,whichisformedfromthema othmuscleintherenalp elvisfunnelsurineviap ,whereastherenalveinsreturncleansedblo o ,vein,andrenalp elvisarearrangedinananterior-to-p enStax-CNXmo rstdividesintosegmentalarteries,followed byfurtherbranchingtoforminterlobararteri esthatpassthroughtherenalcolumnstoreacht hecortex(Figure3(Blo o dFlowintheKidney)).

4 Theinterlobararteries,inturn,branchintoa rcuatearteries,corticalradiatearteries,a ndthenintoa erentarteriolesserviceab o dFlowintheKidneyFigure3 Nephronsarethe functionalunits ofthekidney;theycleansetheblo o erentarteriolesformatuftofhigh-pressurec apillariesab out200 mindiameter, thisisBowman' ' ,theseglomerularcapillaries ltertheblo o ,thecapillariesformasecondarteriole,thee erentarteriole(Figure4(Blo o dFlowintheNephron)). enStax-CNXmo dule:m464295acapillarynetworkaroundthemo redistalp ortionsofthenephrontubule,thep eritubularcapillariesandvasarecta,b ltrateprogressesthroughthenephron,thesec apillarynetworksrecovermostofthesolutesa ndwater, ed(theglomerulus)drainsintoavesselthatin turnformsasecondcapillaryb ed,thede nitionofap ortalsysteminwhichanarterioleisfoundb etweenthe rstandsecondcapillaryb eds.

5 (Portalsystemsalsolinkthehyp othalamustotheanteriorpituitary,andthebl o o dvesselsofthedigestivevisceratotheliver. ) enStax-CNXmo dule:m464296 Blo o dFlowintheNephronFigure4:Thetwocapillary b edsareclearlyshowninthis erentarterioleistheconnectingvesselb etweentheglomerulusandthep enStax-CNXmo dule:m464297:Visitthislink2toviewaninter activetutorialofthe owofblo o ,itiseasytoidentifythecortex;itapp oththeproximalconvolutedtubules(PCTs) opofHenlethatdo esnotdipb out15p ercentofnephronshavelonglo ,thestructureofthekidneyisdividedintotwo principleregions thep out25p ,blo o dvessels,lymphvessels, , erkidney;thesearethe functionalunits. Acapillaryb ed,theglomerulus, ltersblo o dandthe ltrateiscapturedbyBowman' ortalsystemisformedwhentheblo o d owsthroughasecondcapillaryb edsurroundingtheproximalanddistalconvolu tedtubulesandthelo ltrateispro cessedand nallygatheredbycollectingductsthatdraini ntotheminorcalyces,whichmergetoformma jorcalyces;the ltratethenpro ceedstotherenalp elvisand ( ) ( ) ://op o d ow5 enStax-CNXmo ( )Therightkidneyisslightlylowerb ( )Whatanatomicalstructuresprovideprotecti ontothekidney?

6 Exercise5( )Howdo estherenalp ortalsystemdi erfromthehyp othalamo hyp ophysealanddigestivep ortalsystems?Exercise6( ) enStax-CNXmo dule:m464299 SolutionstoExercisesinthisMo duletoExercise( )DtoExercise( )AtoExercise( )AtoExercise( )Retrop eritonealanchoring,renalfatpads, ( )Therenalp ortalsystemhasanarteryb etweenthe rstandsecondcapillaryb ( )Thestructuresfoundintherenalhilumareart eries,veins,ureters,lymphatics, nition1:Bowman'scapsulecup-shap edsacklinedbyasimplesquamousepithelium(p arietalsurface)andsp ecializedcellscalledp o do cytes(visceralsurface)thatparticipateint he ltrationpro cess;receivesthe ltratewhichthenpassesontothePCTsDe nition2:calycescup-likestructuresreceivi ngurinefromthecollectingductswhereitpass esontotherenalp elvisandureterDe nition3:corticalnephronsnephronswithlo opsofHenlethatdonotextendintotherenalmed ullaDe nition4:distalconvolutedtubulesp ortionsofthenephrondistaltothelo opofHenlethatreceivehyp osmotic ltratefromthelo opofHenleandemptyintocollectingductsDe nition5:e erentarteriolearteriolecarryingblo o dfromtheglomerulustothecapillaryb edsaroundtheconvolutedtubulesandlo opofHenle;p ortionofthep ortalsystemDe nition6:glomerulustuftofcapillariessurro undedbyBowman'scapsule.

7 Lterstheblo o dbasedonsizeDe nition7:juxtamedullarynephronsnephronsad jacenttotheb orderofthecortexandmedullawithlo opsofHenlethatextendintotherenalmedullaD e nition8:lo opofHenledescendingandascendingp ortionsb etweentheproximalanddistalconvolutedtubu les;thoseofcorticalnephronsdonotextendin tothemedulla,whereasthoseofjuxtamedullar ynephronsdoextendintothemedullaDe nition9:nephronsfunctionalunitsofthekidn eythatcarryoutall ltrationandmo di cationtopro duceurine;consistofrenalcorpuscles,proxi malanddistalconvolutedtubules,anddescend ingandascendinglo opsofHenle;drainintocollectingductsDe nition10: enStax-CNXmo dule:m4642910De nition11:p eritubularcapillariessecondcapillaryb edoftherenalp ortalsystem;surroundtheproximalanddistal convolutedtubules;asso ciatedwiththevasarectaDe nition12:proximalconvolutedtubules(PCTs) tortuoustubulesreceiving ltratefromBowman'scapsule;mostactivepart ofthenephroninreabsorptionandsecretionDe nition13:renalcolumnsextensionsoftherena lcortexintotherenalmedulla;separatesther enalpyramids;containsblo o dvesselsandconnectivetissuesDe nition14:renalcorpuscleconsistsoftheglom erulusandBowman'scapsuleDe nition15:renalcortexouterpartofkidneycon tainingallofthenephrons.

8 Somenephronshavelo opsofHenleextendingintothemedullaDe nition16:renalfatpadadip osetissueb etweentherenalfasciaandtherenalcapsuleth atprovidesprotectivecushioningtothekidne yDe nition17:renalhilumrecessedmedialareaoft hekidneythroughwhichtherenalartery,renal vein,ureters,lymphatics,andnervespassDe nition18:renalpapillaemedullaryareaofthe renalpyramidswherecollectingductsemptyur ineintotheminorcalycesDe nition19:renalpyramidssixtoeightcone-sha p edtissuesinthemedullaofthekidneycontaini ngcollectingductsandthelo opsofHenleofjuxtamedullarynephronsDe nition20:vasarectabranchesofthee erentarteriolesthatparallelthecourseofth elo opsofHenleandarecontinuouswiththep eritubularcapillaries;withtheglomerulus, formap