Forma&on of Concentrated Urine · •Concentrated urine has a deeper yellow color •Drugs, vitamin...
Transcript of Forma&on of Concentrated Urine · •Concentrated urine has a deeper yellow color •Drugs, vitamin...
Chapter 25: Urinary System
Forma&onofConcentratedUrine• An#diure#chormone(ADH)inhibitsdiuresis
• DCTandcollec#ngductbecomepermeabletowater
• Thisequalizestheosmolarityofthefiltrateandtheinters##alfluid
• Risesfrom300mOsmto1200mOsmasurinemovethroughmedulla
• InthepresenceofADH,99%ofthewaterinfiltrateisreabsorbed
Forma&onofConcentratedUrine
• ADH‐dependentwaterreabsorp#on
• Calledfaculta#vewaterreabsorp#on
• ADHisthesignaltoproduceconcentratedurine
• Thekidneys’abilitytoresponddependsuponthehighmedullaryosmo#cgradient
• Ifbloodplasmarisesabove300mOsm
• ADHwillbereleasedtodilute
Chapter 25: Urinary System
Forma&onofDiluteandConcentratedUrine
Figure 25.15a, b
RenalClearance
• Thevolumeofplasmathatisclearedofapar#cularsubstanceinoneminute
• Inulin
• Standardforcomparisonwhichiscompletelyremoved(completerenalclearance)
• Plantpolysaccharide
• Renalclearancetestsareusedto:
• DeterminetheGFR
• Detectglomerulardamage
• Followtheprogressofdiagnosedrenaldisease
Chapter 25: Urinary System
RenalClearance
RC=UV/P
RC=renalclearancerate
U=concentra#on(mg/ml)ofthesubstanceinurine
V=flowrateofurineforma#on(ml/min)
P=concentra#onofthesamesubstanceinplasma
• Iflessthaninulin‐somecleared,par#allyreabsorbed
• Ifzero‐nonecleared,allreabsorbed
• Ifgreaterthaninulin‐allcleared,nonereabsorbed
PhysicalCharacteris&csofUrine• Colorandtransparency
• Clear,paletodeepyellow(amber‐duetourochrome)
• Concentratedurinehasadeeperyellowcolor
• Drugs,vitaminsupplements,anddietcanchangethecolorofurine
• Cloudyurinemayindicateinfec#onoftheurinarytract
• OrbacteriaifleYstanding
Chapter 25: Urinary System
PhysicalCharacteris&csofUrine• Odor
• Freshurineisslightlyaroma#c
• Standingurinedevelopsanammoniaodor
• NH4⇒NH3
• Somedrugsandvegetables(asparagus)altertheusualodor
• 40‐50%ofpopula#onmakeasparaguspee!
• Singleautosomaldominantgeneproductcatalyzesasparagustothioesters
• Smaller%unabletosmellit!
• Fruity/sweet
• Diabetesmellitus
PhysicalCharacteris&csofUrine
• pH
• Slightlyacidic(pH6)witharangeof4.5to8.0
• DietcanalterpH
• Moreprotein=moreacidic
• Morevegetables=morealkaline
• Specificgravity
• Rangesfrom1.001to1.035
• Isdependentonsoluteconcentra#on
Chapter 25: Urinary System
ChemicalComposi&onofUrine
• Urineis95%waterand5%solutes
• Urea‐Deamina#onofproteins
• Uricacid‐Catabolismofnucleicacids
• Crea#nine‐Metaboliteofcrea#nefrommuscle#ssue
• Othernormalsolutesinclude:
• Sodium,potassium,phosphate,andsulfateions
• Calcium,magnesium,andbicarbonateions
• Abnormallyhighconcentra#onsofanyurinarycons#tuentsmayindicatepathology
Ureters
• Slendertubesthatconveyurinefromthekidneystothebladder
• Moveretroperitonealatpelviccavity
• Uretersenterthebaseofthebladderthroughtheposteriorwall
• Preventsbackflowofurineintotheureters
Chapter 25: Urinary System
Ureters• Uretershaveatrilayeredwall
• Transi#onalepithelialmucosa
• Smoothmusclemuscularis
• Innerlongitudinal,outercircular
• Peristal#ccontrac#ons
• Fibrousconnec#ve#ssueadven##a
• Uretersac#velypropelurinetothebladderviaresponsetosmoothmusclestretch
UrinaryBladder
• Smooth,collapsible,muscularsac
• Temporarilystoresurine
• Retroperitonealonthepelvicfloor
• Posteriortothepubicsymphysis
• Trigone–triangularareaoutlinedbytheopeningsfortheuretersandtheurethra
• Clinicallyimportantbecauseinfec#onstendtopersistinthisregion
Chapter 25: Urinary System
UrinaryBladder
• Thebladderwallhasthreelayers
• Transi#onalepithelialmucosa
• Triplemuscularlayer‐detrusormuscle
• Innerandouterlongitudinal
• Middlecircular
• Afibrousadven##a
• Thebladderisdistensibleandcollapseswhenempty
• Asurineaccumulates,thebladderexpandswithoutsignificantriseininternalpressure
UrinaryBladder
Figure 25.18a, b
Chapter 25: Urinary System
Urethra
• Thinwalledmusculartube
• Drainsurinefromthebladder
• Mucosa
• Transi#onalepitheliumnearbladder
• Pseudostra#fiedcolumnarinmiddleregion
• Stra#fiedsquamousnearexit
Urethra• Sphincterskeeptheurethraclosedwhenurineisnotbeingpassed
• Internalurethralsphincter–involuntarysphincteratthebladder‐urethrajunc#on
• Smoothmuscle
• Externalurethralsphincter–voluntarysphincter
• Surroundsurethraasitpassesthroughtheurogenitaldiaphragm
• Skeletalmuscleofpelvicfloor
• Levatoranimuscle–voluntaryurethralsphincter
Chapter 25: Urinary System
Urethra• Femaleurethrais#ghtlyboundtotheanteriorvaginalwall
• Posteriortopubicsymphysis
• 1.5”long
• Externalopeninganteriortothevaginalopeningandposteriortotheclitoris
• Maleurethra(~8”)hasthreenamedregions
• Prosta#curethra–runswithintheprostategland
• Membranousurethra–runsthroughtheurogenitaldiaphragm
• Spongy(penile)urethra–passesthroughthepenisandopensviatheexternalurethralorifice
• Conduc#onofurineandsemen
Urethra
Figure 25.18a. b
Chapter 25: Urinary System
Micturi&on(VoidingorUrina&on)• Theactofemptyingthebladder
• Distension⇒stretch/mechanoreceptors⇒reflexarc⇒sacralspinalcord⇒brain⇒inhibitoryors#mulatoryresponse
• S#mulatory
• Efferentparasympathe#cpelvicnervestocontractdetrusormuscleandrelaxinternalurethralsphincter⇒urinemovespastIUS⇒externalurethralsphinctervoluntarilyrelaxed⇒urina#on
• Inhibitory
• Efferentsympathe#cnervesrelaxdetrusormuscle⇒contractIUS⇒stopsurine⇒EUSremainsclosed⇒nourina#on
Micturi&on(VoidingorUrina&on)
Figure 25.20a, b
Chapter 25: Urinary System
Micturi&on(VoidingorUrina&on)
• Incon#nence
• Lackofvoluntarycontroloverurina#on
• Normalininfants
• Olderchildrenoradults
• Ususuallyduetoemo#onalornervoussystemproblems
• Retension
• Inabilitytovoidurine
• Duetoobstruc#oninurethraorbladder
• UTI’s,prosta##s,prostatecancer