Fisiologi Sistem Urinaria 2.2-2015

8/17/2019 Fisiologi Sistem Urinaria 2.2-2015

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Fisiologi Si

Urinari

C h a p t e r26



Capaian Pembelajaran

Mahasiswa mampu menjelaskan:

1. komponen system urinarius beserta fungsi utamanya2. proses pembentukan urin dalam nefron

3. laju filtrasi glomerulus beserta faktor-faktor yang mempe

4. mekanisme reabsorpsi dan sekretorik yang diperankan

. pengaruh hormone antidiuretik dan aldosteron terhadap

dan konsentrasi urin



Capaian Pembelajaran

Mahasiswa mampu menjelaskan:

". karakteristik urin yang normal

#. fungsi ureter$ !esi%a urinaria$ dan uretra

&. mekanisme %ontrol !olunteer dan in!olunter serta menje

refleks berkemih

'. integrasi antara system urinarius dengan system lainnya



(un%tion

• )*%retion + )limination

• ,omeostati% regulation of blood plasma• egulating blood !olume and blood pressure

• egulating eritro%yt produ%tion

• egulating plasma %on%entrations of ions

• ,elping to stabilie blood p,

• /onser!ing !aluable nutrients



/oordination with 0thers

• digesti!e

• respiratory• %ardio!as%ular



egulation

• utoregulation

• utonomi% ner!ous system• )ndo%rine



itrogenous astes

• rea

•

proteins→

amino a%ids→

,2 remo!ed→forms ammonia$ li!er %on!erts to urea

• ri% a%id

• nu%lei% a%id %atabolism

• /reatinine

• %reatinine phosphate %atabolism

• enal failure

• aotemia: nitrogenous wastes in blood

• uremia: to*i% effe%ts as wastes a%%umulate



)*%retion

• 5eparation of wastes from body fluids and eliminating the

• respiratory system: /02

• integumentary system: water$ salts$ la%ti% a%id$ urea

• digestive system: water$ salts$ /02$ lipids$ bile pigments$ %hole

• urinary system: many metaboli% wastes$ to*ins$ drugs$ hormon

salts$ ,6 and water



ephrons

• nit fun%tional of kidney

•

/orti%al nephrons 7&89• short nephron loops

• efferent arterioles bran%h off peritubular %apil

• u*tamedullary nephrons 7189

• !ery long nephron loops$ maintain salt gradie

%onser!e water • efferent arterioles bran%h off !asa re%ta$ bloo

medulla



ephron ;iagram



• <rodu%tion of filtrate

• eabsorption of organi% nutrients

• eabsorption of water and ions

• 5e%retion of waste produ%ts into tubular fluid

ephron fun%tions in%lude:



enal /orpus%le

=lomerular filtrate %olle%ts in %

spa%e$ flows into renal tubul



(iltration Membrane ;iagram



(iltration Membrane

• (enestrated endothelium

• #>-'>nm pores e*%lude blood %e

• ?asement membrane

• proteogly%an gel$ negati!e %harg

e*%ludes mole%ules @ &nm

• (iltration slits

•

podo%yte arms ha!e pedi%els witnegati!ely %harged filtration slits$

parti%les A 3nm to pass



(iltration <ressure



=lomerular (iltration ate 7=(9

• (iltrate formed per minute

• (iltration %oeffi%ient 7Bf 9 depends on permeability and surarea of filtration barrier

• =( C (< * Bf ≈ 12 mlDmin or 1&> EDday

• ''8 of filtrate reabsorbed$ 1 to 2 E urine e*%reted



)ffe%ts of =( bnormalities

• ↑=($ urine output rises → dehydration$ ele%trolyte depl

• ↓=( → wastes reabsorbed 7aotemia possible9• =( %ontrolled by adjusting glomerular blood pressure

• autoregulation

• sympatheti% %ontrol

• hormonal me%hanism: renin and angiotensin



Fubular eabsorption and 5e%retion



• eabsorption and se%retion modified by %arrier mediated

transport• (a%ilitated diffusion

• %ti!e transport

• /otransport

• /ountertransport

• /arrier proteins ha!e a transport ma*imum 7Fm9

• ;etermines renal threshold

/arrier Mediated Fransport



<ro*imal /on!oluted Fubules 7</F9

• eabsorbs "8 of =( to peritubular %apillaries

• =reat length$ prominent mi%ro!illi and abundant mito%hona%ti!e transport

• eabsorbs greater !ariety of %hemi%als than other parts o

nephron

• trans%ellular route - through epithelial %ells of </F

• para%ellular route - between epithelial %ells of </F

• Fransport ma*imum: when transport proteins of plasma

membrane are saturatedG glu%ose @ 1&> mgDdE remains

7gly%osuria9



</F

</F



</F

F b l 5 ti f </F



Fubular 5e%retion of </F

and ephron Eoop

• aste remo!al

• urea$ uri% a%id$ bile salts$ ammonia$ %ate%holamines$ many dr• %id-base balan%e

• se%retion of hydrogen and bi%arbonate ions regulates p, of b

fluids

• <rimary fun%tion of nephron loop

• water %onser!ation$ also in!ol!ed in ele%trolyte reabsorption

b ti d ti t th ;/F



• ;/F performs final adjustment of urine

• %ti!e se%retion or absorption

• bsorption

• Fubular %ells a%ti!ely resorb a6 and /l-

• Hn e*%hange for potassium or hydrogen ions 7se%rete

eabsorption and se%retion at the ;/F



Fubular 5e%retion and 5olute eabsorption at the ;/



Fubular 5e%retion and 5olute eabsorption at the ;/

;/F and /olle%ting ;u%t



;/F and /olle%ting ;u%t

• )ffe%t of aldosterone

• ↓ ?< %auses angiotensin HH formation

•angiotensin HH stimulates adrenal %orte*

• adrenal %orte* se%retes aldosterone

• aldosterone promotes a6 reabsorption

• a6 reabsorption promotes water reabsorption

• water reabsorption ↓ urine !olume

•?< drops less rapidly

;/F and /olle%ting ;u%t 2



;/F and /olle%ting ;u%t 2

• )ffe%t of atrial natriureti% fa%tor 7(9

• ↑ ?< stimulates right atrium

• atrium se%retes (

• ( promotes a6 and water e*%retion

• ?< drops

• )ffe%t of ;,

• dehydration stimulates hypothalamus

• hypothalamus stimulates posterior pituitary

• posterior pituitary releases ;,

• ;, ↑ water reabsorption• urine !olume ↓

/olle%ting ;u%t /on%entrates rine



/olle%ting ;u%t /on%entrates rine

• 0smolarity 4*

in medulla• Medullary por

permeable to

to a/l

/ounter%urrent Multiplier




• e%aptures a/l and returns it to renal medulla

• ;es%ending limb

• reabsorbs water but not salt

• %on%entrates tubular fluid

• s%ending limb

• reabsorbs a6$ B6$ and /l-

• maintains high osmolarity of renal medulla

• impermeable to water

• tubular fluid be%omes hypotoni%

• e%y%ling of urea: %olle%ting du%t-medulla• urea a%%ounts for 4>8 of high osmolarity of medulla







/ounter%urrent )*%hange 5ystem



/ounter%urrent )*%hange 5ystem

• (ormed by !asa re%ta

•

pro!ide blood supply to medulla• ;es%ending %apillaries

• a/l diffuses into blood

• s%ending %apillaries

• water diffuses into blood

Maintenan%e of 0smolarity in enal Medulla



Maintenan%e of 0smolarity in enal Medulla

5ummary of Fubular eabsorption and 5e%retion



5ummary of Fubular eabsorption and 5e%retion

5ummary of enal (un%tion



5ummary of enal (un%tion

/omposition and <roperties of rine



/omposition and <roperties of rine• ppearan%e

• almost %olorless to deep amberG yellow %olor due to uro%hrom

breakdown of hemoglobin 7?/Is9

•

0dor - as it stands ba%teria degrade urea to ammonia• 5pe%ifi% gra!ity

• density of urine ranges from 1.>2 -1.>3

• 0smolarity - 7blood - 3>> m0smDE9 ranges from

1>> m0smDE to 1$2>> m0smDE in dehydrated person

• p, - range: 4. - &.2$ usually ".>• /hemi%al %omposition: '8 water$ 8 solutes

• urea$ a/l$ B/l$ %reatinine$ uri% a%id

rine Jolume



rine Jolume

• ormal !olume - 1 to 2 EDday

•

<olyuria @ 2EDday• 0liguria A >> mEDday

• nuria - > to 1>> mE

enal (un%tion Fests



• enal %learan%e: !olume of blood plasma %leared of a wa

in 1 minute• ;etermine renal %learan%e 7/9 by assessing blood and u

samples: / C JD<

• 7waste %on%entration in urine9

• J 7rate of urine output9

•

< 7waste %on%entration in plasma9• ;etermine =(: inulin is neither reabsorbed or se%reted

for this solute =( C renal %learan%e =( C JD<

enal (un%tion Fests



• /reatinine %learan%e:

•

eliminates &4 mg of %reatinine ea%h hour • plasma %reatinine %on%entration of 1.4 mgDdl

• 1>> mlDmin

ormal parameter



p

• ?( : 12>> mlDmin

•

<( : "2 mlDmin• (ra%tion filtration : 2>8

• =( : 12 mlD min

• rin produ%tion : 1-2 mlD menit

ging



g g

• A decline in the number of functional nephrons.

• Fhe total number of kidney nephrons drops by 3>K4> 8 betwee

and &.• A reduction of the GFR.

• de%reased numbers of glomeruli$ %umulati!e damage to the filtr

apparatus in the remaining glomeruli$ and redu%tions in renal blo

• A reduced sensitivity to ADH.

• the distal portions of the nephron and %olle%ting system be%omeresponsi!e to ;,.

• Eess reabsorption of water and sodium ions$ and more sodium

in urine.

Documents

Fisiologi Sistem Urinaria 2.2-2015