URINARYSYSTEM

HumanAnatomyUnit3

InAnatomyToday

Components

• Kidneys• Ureters• Urinarybladder• Urethra

Functions

• Storageofurine– Bladderstoresupto1Lofurine

• Excretionofurine– Transportofurineoutofbody

• Regulation:– PlasmapH– Bloodvolume/pressure– Plasmaionconcentrations(Ca2+,Na+,K+,CL-)– Assistliverindetoxification,aminoacidmetabolism

KidneyGrossAnatomy• Retroperitoneal

– Anteriorsurfacecoveredwithperitoneum

– Posteriorsurfacedirectlyagainstposteriorabdominalwall

• SuperiorsurfaceataboutT12

• InferiorsurfaceataboutL3• Ureters enterurinary

bladderposteriorly• Leftkidney2cmsuperiorto

right– Sizeofliver

StructureoftheKidney

• Hilum=thedepressionalongthemedialborderthroughwhichseveralstructurespass– renalartery– renalvein– ureter– renalnerves

SurroundingTissue• Fibrouscapsule

– InnermostlayerofdenseirregularCT

– Maintainsshape,protection• Adiposecapsule

– Adiposectofvaryingthickness– Cushioningandinsulation

• Renalfascia– DenseirregularCT– Anchorskidneytoperitoneum

&abdominalwall• Paranephric fat

– Outermost,adiposeCTbetweenrenalfasciaandperitoneum

FrontalSectionoftheKidney• Cortex

– Layerofrenaltissueincontactwithcapsule

– Renalcolumns– partsofcortexthatextendintothemedullabetweenpyramids

• Medulla– Stripedduetorenal

tubules• Renalpyramids

– 8-15presentinmedullaofadult

– Conicalshape– Widebaseat

corticomedullary junction

FlowofFiltrate/Urine• Collectingducts

– Collectfrommultiplenephrons• Minorcalyx

– Collectfromeachpyramid• Majorcalyx

– Collectfromminorcalyx• Renalpelvis

– Collectsfromcalyces,passesonto

• Ureter– Collectsfrompelvis

• UrinaryBladder– Collectsfromureters

Histology

RenalCortex RenalMedulla

RenalTubules

• Nephron– functionalunitofthekidney.

• Eachkidneycontainsapproximately1millionnephrons

• Formurinebyfilteringandadjustingcompositionofbloodcarriedbyrenalvasculature

RenalPortalSystem

RenalPortalSystem

HistologicalStructureofaNephron• Renalcorpuscle

– Glomerulus– Bowman’scapsule

• Renaltubules– Proximalconvolutedtubule– DescendinglimbofLOH– LoopofHenle– AscendinglimbofLOH– Distalconvolutedtubule– Collectingduct

• Associatedbloodvessels- Peritubularcapillaries- Vasarecta

TypesofNephrons

TheGlomerulus

• Bowman’scapsule– Linedwithpodocytes

• Glomerulus– Capillarybed– Bulkflow

• Afferentarteriole• Efferentarteriole

TheCollectingSystem• Collectingductsreceive

filtratefromDCTofnephrons

• Collectingductsemptyintominorcalyces

• Minorcalycesemptyintomajorcalyces

• Majorcalycesdrainintorenalpelvis

• Renalpelvisdrainsintoureter– Nowurine

TheUreters• Expandabletubesthatexittherenalpelvis

• 3walls– Mucosa

• Transitionalepithelium– Muscularis

• smoothmusclelayer– Adventitia

• protectivefibrousCT– Uretersdrainintotheposteriorportionoftheurinarybladder

TheUrinaryBladder

• Functionstostoreurine• Structure– Rugae

• macroscopicfoldsasinthestomach

• flattenwhentheurinarybladderisdistended

– Trigone• triangularregionofthebladder

• norugae• locationofopeningstotheuretersandurethra

HistologyoftheUrinaryBladder

• Mucosallining– transitionalepithelium

• Submucosa– fibrousCT

• Muscularis– detrusor muscle

• 3layersofsmoothmuscle

• Adventitia– looseCT– visceralperitoneum

TheFemaleUrethra

• Drainsurinefromurinarybladdertoexterior

• 1-2inches• higherriskforbladderinfections

TheMaleUrethra

• 3regions:– prostatic– membranous– penile

HistologyoftheUrethra

• Mucosa– variesfrombladdertoexteriorespeciallyinmales

• Muscularis layer• Adventitia• Sphincters– internal=smoothmuscle(involuntary)

– external=skeletalmuscle(voluntary)