Physio - Chapter 5

8/19/2019 Physio - Chapter 5

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CHAPTER 5: Transport of Solutes and Water

Intracellular Fluid

• Fluid inside the cells and occupies intracellular space

• High in K + and low in Na+ and Cl-

Extracellular Fluid

• Fluid outside the cells and occupies extracellular space

• Low in K + and high in Na+ and Cl-

Na-K Pump = utilied !" cell to maintain the optimal ion contents

in and out o# the cell

$wo %a&or Constituents o# the ECF

• Plasma

• Interstitial Fluid

Protein-Free Plasma = 'Plasma Content in me()L* ) ,.

Efect o Protein Charge

• Non-charged /oluteo 0/uch as 1L2C3/E4 Lipid and Protein 5olume is

the onl" correction !ecause plasma proteins

are net negati5e chargedo 6etain cations in plasma

• Cation Conc o# Protein-Free Plasma = Lowered !" 78

• 9nion Conc : = Higher !" 78

All Body Fluids Have Approx Same Osmolality Each !uid

has E"ual #um$ers o % and & Charges

3smolalit"o descri!es the total concentration o# all particles

that are #ree in a solutiono expressed as the num!er o# osmoticall" acti5e

particles per ;ilogram o# water 0<mosmol);g

o# H<3

Electroneutrality

9ll solutions must respect the principle !ul; o#

electroneutralit" $he num!er o# positi5e charges in the

o5erall solution must !e the same as the num!er o#

negati5e charges

9nion 1ap = di>erence !etween anions and cations in

!lood plasma

' Hydrostatic Pressure = Vessel to intracellular fuid

' Oncotic Pressure = H2O accumulates in cells

Solute (ransport Across Cell )em$ranes

In Passive, Noncoupled transport across a permeable membrane,

a solute moves down its electrochemical gradient

• Electrochemical 1radiento the dri5ing #orce that determines the passi5e

transport o# solutes across the mem!raneo di>erence !etween the actual mem!rane

potential and e(uili!rium potential #or an"

speci?c set o# intra and extra coonco includes the contri!ution #rom the

concentration gradient o# the soluteo @eterminants o# Electrical Potential Energ"

Concentration 1radient

Aoltage @i>erence

• Noncoupled $ransporto %o5ement o# a su!stance means the

mo5ement o# it across the mem!rane is not

directl" coupled to the mo5ement o# other

solutes

@i> EC)IC Conc o# /oln with No Aoltage @i> = oncentration

!radient as dri5ing #orce

/ame E)IC Conc o# /oln BI$H Aoltage @i> = "lectrical !radient as

dri5ing #orce

INFL2 D mo5ement o# solute #rom outside to inside

EFFL2 D mo5ement o# solute #rom inside to outside

2nidirectional D mo5ement across the mem!rane in one direction

Net Flux 0Net $ransport 6ate D sum o# two unidirectional uxes

No driving #orce = "$%I&I'(I%) = No net transport

/tead" /tate D conditions related to a su!stance do not change

with time

Bhere

x = 5alence o# solute x = net dri5ing #orce 0&ou)m4xo = conc outside Gi D Go = mem!rane potentixi = conc inside 6 = gas constantF = Farada"s Constant

I# NE$ @6IAIN1 F36CE is not E63 = not in e(uili!riumNerst E(uation = descri!es the conditions when an ion is ine(uili!rium across a mem!raneIn *I)P&" +I%*ION, the fu- o# an uncharched substancethrough membrane lipid is directly proportional to itsconcentration gradient.*ntegral )em$rane Proteins. $"pes o# Protein Pathwa"s

• Poreo 9lwa"s open

o Ex, Porins in the outer mem!ranes o#

mitochondriaJ c"totoxic pore-#orming proteins =



Per#orin released !" l"mphoc"tes anda(uaporin channels

• Channelo 9lternatel" open and closed !ecause it is

e(uipped with a mo5a!le !arrier or gateo Process is called gating

o 1ated Pore not a 1ated Channel 0Ex, IonChannels4

• Carrierso /urrounds a conduit that ne5er o>ers a

continuous transmem!rane path !ecause it ise(uipped with at least two gates that are ne5eropen at the same time

Porins

• Large-sie pores #ound in outer mem!rane o# gram-

negati5e !acteria and mitochondriao %itochondrial Porin D allows solutes as large as

7;@a to di>use passi5el" #rom c"tosol into themitochondrial mem!rane

Per#orin D pore-#orming protein

released !" c"totoxic $ l"mphoc"tes to;ill their target cells

Eg Complement Cascade D monomer

o# Co Nuclear Pore Complex 0NPC4

6egulates trac into and out o# the

nucleus 5ia acti5e transport Can transport huge molecules

in5ol5ing 9$P h"drol"sis Has 929P36IN #or passi5e transport

*on+,ated Channels

• Consists one or more pol"peptide su!units with a-helical mem!rane spanning segments

• Functional Componentso 1ate D determines whether channel is open or

closedo /ensors D respond to one o# se5eral signals

Change in mem!rane 5oltage

/econd-messenger s"stems D acts at

the c"toplasmic #ace o# the mem!raneprotein

Ligands D!ind to extracellular #ace o#

the mem!rane proteino /electi5it" Filter D determines the classes o#

ions or the particular ions that ha5e access tothe channel pore

o

3pen Channel Pore D pro5ides continuouspathwa" when it assumes open con#ormation!etween two sides o# mem!rane so ions canow through it passi5el" !" di>usion until thechannel closes again

• Channelso Na Channels

Passi5e transport

Aoltage-1ated Na Channels

• 6esponsi!le in generatingaction potential

o K Channels

Fairl" close to ero or somewhat

positi5e

%o5e outward the cell

Has a ma&or role in generating a

resting mem!rane 5oltage that isinside-negati5e

Has a ;e" in excita!ilit" cells where

these channels help terminate actionpotential

o Ca Channels

9lwa"s strongl" negati5e

%o5e into the cell

6apidl" enters the cell down a steep

electrochemical gradient Pla"s a 5ital role in transmem!rane

signaling #or !oth excita!le and non-excita!le cells and generating actionpotential

o Proton Channels

H+ dri5ing #orce generall" tends to

mo5e H into cells i# H5M are open Normall" closed and acti5ates onl"

when the mem!rane depolaries orc"toplasm acidi?es

Help mediate H extrusion #rom cell

during states o# strong mem!ranedepolariation 0during action potential4or se5ere intracellular acidi?cation

o 9nion Channels

%ostl" negati5e electrochemical

dri5ing #orce

Carrier )ediated (ransport Systems

• $rans#ers a !road range o# ions and organic solutesacross the plasma mem!rane

• eha5e according to the general ;inetic scheme

• Can mediate onl" passi5el" or downhill

O Km = 9nit"o /olute Carrier /uper#amil"

@o not either h"drol"e 9$P or couple

to an electron transport chain @i>ers in

• %olecular mechanism

• Kinetic properties

• 6egulation

• /ites o# mem!rane targeting• $issues which the" are

expressed

• @e5elopmental stage at

which the" are expressed 1L2$M = glucose transporter on the

cell sur#ace 1L2$Q = present in the intracellular

sur#aces 2rea $ransporter

3rganic Cation $ransporter

#a-. % Pump & most important primary active transporter/utili0es 1P to e-trude Na and upta3e 4

• 9cti5e $ransport = process that can trans#er a solute

uphill across a mem!rane against electrochemicalgradient

o Primar" 9cti5e $ransport D dri5ing #orce neededto cause net trans#er o# solute againstelectrochemical gradient comes #rom 9$P 0eg,carr"ing hea5ing material to airR P2%P/energied !" 9$Pases4

o /econdar" 9cti5e $ransport D dri5ing #orce is

pro5ided !" coupling uphill and downhillmo5ement o# one or more solute which is a#a5ora!le electrochemical gradient exists 0egseesaw4

Na)K Pump

• 3ccurs !etween a and ! su!unitso S-su!unit

has M transmem!rane segments

catal"tic su!unit

o T-su!unit

one transmem!rane segment

essential #or proper assem!l" and

targeting o# Na-K pump

• Exclusi5e to the !asolateral mem!rane

• 6esponsi!le #or low Na and high K relati5e to the ECF

• %em!er o# large super#amil" o# pumps ;nown as :"56"2

1Pses or P6type 1Pase7

• $wo Con#ormational /tateso EM - !inding sites #or ions #ace inside o# cello E< D !inding sites #ace outside the cell

• /$EP/



o UM 9$P-!ound EM 9$P state, 9#ter pump has

released two K to the ICFJ Na-!inding sites #acethe ICF and ha5e high anities to Na

o U< Na-!ound EM 9$P .Na /tateo U. 3ccluded EM D P 0.Na+ /tate4 9$P

phosphorelates lea5ing 9@P trigerring minorcon#ormational change in EM #orm the pump nowoccludes . Na ions within the permeationpathwa" 0Na inaccessi!le to ICF)ECF4

o UQ @eocccluded E<-P .Na /tate, EM to E< ha5ing

two e>ects 0M4 Pump !ecomes deoccluded thatNa-!inding site is now open to the ECF 0<4 Na

anities o# these !inding sites decreaseo U7 Empt" E<-P state, . Na dissociate into ECF

and protein undergoes minor con#ormationalchange to empt" E<-P #orm which has highanit" to K

o UV K-ound E<-P <K /tate, < K !ind to pumpo UW 3ccluded E<-K /tate, 6elease o# inorganic

phosphate into ICFo UX @eocludded EM 9$P <K /tate, E< to EM !" 9$P,

E>ects 0M4 pump !ecomes deocludded 0<4Kanities decreased

o 9CK $3 /$EP M

• loc;erso Has high anit" to ECF o# E<-P Cellular K 0/tep

74o Cardiac 1l"cosides

3ua!ain

@igoxin D widel" used #or caridiac

conditions

Other P+type A(Pases

• H-K Pumpo In parietal cells o# gastric glandso Excretes H+ to the apical mem!rane to the

lumen and upta;es K +• Ca<+ Pumps 0Plasma %em!rane Ca 9$Pase-P%C94

o Extrudes Ca #rom cellR Inux o# H in

sarcoplasmic reticulum in muscle cells

• 3ther Pumpso Copper Pump 9$PW D mutated in Bilsons dse

F+(ype and /+(ype A(Pases (ransport H%

F-t"pe or FoFM 9$Paseso 07;@ao Fx

$he hand acts as a tur!ine that

roteates in the plane o# mem!raneJdri5en !" the H ions that ow through

the tur!ine-down the Helectrochemical gradient into themitochondrion

/tic; is an axle 0" and E su!units o#

FM4 that rotates with the tur!ine

Cand" 0a and ! su!units o# FM4 is a

stationar" chemical #actor"J energied!" the rotating axle that s"nthesiesone 9$P molecule #or each M<Y tuno# tur!ine

A-t"pe H+ Pumpo Has l"sosomesJ endosomes and secretor"

5esiclesJ storage 5esicles and the 1olgi9pparatus contain so-called 5acuolar-t"pe 05-t"pe4 H-9$Pase that pumps H #rom c"toplasm tointerior organelles

o Has V su!units

A(P+$inding Casettes 1ABC2 (ransporters 3 can act ashannel, Pumps or (egulators

• 9CM /u!#amil"o Important in mediating eZux o# phospholipids

and cholesterol #rom macrophages and othercells

• %@6 /u!#amil"o %ultidrug 6esistance $ransporterso 9$Pases and primar" acti5e transporters

%@6M)P 1l"coprotein = extrudes

cationic meta!olites and drugs acrosscell mem!rane/ important andclinicall" antagonistic in cancer pxpumping anticancer drugs

• %6P)CF$6 /u!#amil"o Fx as low-conductance Cl- channel as well as

regulator o# other ion channelso Has two mem!rane spanning domains 0%/@M

and %/@<4 with V mem!rane-spanningsegments

o Has < nucleotide-!inding domains 0N@M and

N@<4o Has Protein Kinase 9 and C as regulator"

domainso $wo %echanisms o# 9$P regulating CF$6 Cl

Channel Protein phosphor"lation

Interaction with the nucleotide-!inding

domains

Cotransporters One Class o Secondary Active(ransporters are ,enerally 4riven $y the Energy o the*n5ardly 4irected #a% ,radient /econdar" 9cti5e $ransporters = dri5ing #orce is pro5ided !"coupling uphill and downhill mo5ement o# one or more solutewhich is a #a5ora!le electrochemical gradient exists 0eg seesaw4

• Cotransporters 0/"mporters4



o Intrinsic mem!rane proteins that mo5e the

dri5ing solute 0gradient pro5ides the energ"4and dri5en solutes 0which mo5e uphill4 in thesame direction

• Exchangers 09ntiporters4

Examples o# Cotransporters

• Na)1lucose Cotransporter 0/1L$4o Located at apical mem!rane o# cells that line

the PC$ and /mall Intestineo elongs to the /LC7 #amil" consisting o# a

single su!unit /1L$M = mo5es < Na with each

glucose molecule /1L$< and . = mo5e M Na with each

gluose

• Na-@ri5en Cotransporters #or 3rganic /oluteso Na-@ri5en 99 $ransporters = !elong to /LCV

and /LC.X Na-coupled cotransporter #or

%onocar!ox"latesJ @i and $ri

• Na)HC3. Cotransporterso elongs to /LCQR ;e"group o# acid-!ase

transporters 06egulation o# intracellular pH4o In the !asolateral mem!ranes

Electrogenic = EZux o# HC3. M.

0NaHC3.4 Electroneutral = Inux o# HC3. MM

• Na-@ri5en Cotransporters #or Inorganic 9nionso NaPi = mem!ers o# /LC MWJ < and .Q and

/ul#ate cotransporter 0/LCM.4

• Na)K)Cl Cotransportero elong to /LCM<o Harness energ" o# the inwardl" directed Na+

electrochemical gradient to dri5e theaccumulation o# Cl and K

NKCCM = present in the !asolateral

mem!rane NKCC< = present in the apical

mem!raneo %ediate the uphill Cl transport to cell

o Inhi!ited !" #urosemide and !umetanide which

are called Loop @iuretics !ec the" increaseurine ow !" inhi!iting transport at loop o#Henle

• Na)Cl Cotransportero In the apical mem!rane o# @C$o K+ independentR !loc;ed !" thiaide diuretics

• K)Cl Cotransportero Na-independentR

o Electrochemical gradient is outwardl" directed

!ec it is means to accumulate in the cell

o K Electrochemical gradient is outwardl"directed !ec it is means to accumulate in thecell mo5ing K and Cl inward

o Inside gradient mem!rane potential causes

eZux o# Cl NKKC

Cl-HC3.

• ring Cl into the cell

• Cl Electrochemical gradient isoutwardl" directed !ec it ismeans to accumulate in thecell

• H-@ri5en Cotransporters

o H)oligopeptide cotransporter Pep$M and related

proteins are mem!ers o# /LCM7o Pep$M D electrogenic and responsi!le #or upta;e

o# small peptides #rom the lumen into the cellso# renal PC$ and small intestine

o %ediate the electroneutralJ H-couple ux o#

lactateJ p"ru5ate or other monocar!ox"latesacross the cell mem!ranes o# most tissues o#the !od"

H-dri5en 9mino 9cid Cotransporters

0ex P9$M4D mem!ers o# /LC.V %onocar!ox"late Cotransporter 0ex

%C$M4• Can operate in either the net

inward or outward directionJdepending on the lactate andH gradients across the cellmem!rane

• %o5es lactate out o# cells thatproduce lactate !" gl"col"sis!ut into cells that consumelactate

o @i5alent %etal Ion Cotransporter 0@%$M4

%em!er o# /LCM

Couples the inux o# H to the inux o#

Ferrous Iron 0Fe<+4 as well as to a5ariet" o# other di5alent mealsJ someo# which 0Cd<+J P!<+4 are toxic to cells

Expressed at high le5els in ;idne" and

proximal part o# the /mall Intestine

Exchangers Another Class o Secondary Active(ransporters Exchange o *ons or One Another

3ther ma&or class o# secondar" acti5e transporters is theexchangersJ or antiporters

• Exchangers D intrinsic mem!rane proteins that mo5eone or more :dri5ing[ solutes in one direction and one ormore :dri5en[ solutes in the opposite directionR --exchanges anion #or anion and cation #or cation

o Na-Ca Exchanger

Nearl" u!i(uitous Na-Ca Exchanger0NC4 !elong to /LCX

%ediate the exchange o# .M 0NaCa4

Electrogenic and mo5es net powsiti5e

charge in the same direction as Na Na 0inuxR as primar" 9$4 = Ca 0eZuxR

as secondar" 9$4o Na-H Exchanger 0NHE4

/LC 0MM4

Na 0inux4 H 0eZux4 = pH o# Cell

• NHEMo present in

nonepithelial cellsand !asolateralmem!ranes o#epithelia

o pla"s ma&or role inpHi regulation andcell 5olume

• NHE.o Present at apical

mem!ranes o#se5eral epithelia

o Pla"s ma&or role in

acid secretion or Naa!sorption

3rganic Cation H Exchanger

• /ecretes cationic meta!olitesand drugs across the apical



mem!rane o# renal proximaltu!ule cells and hepatoc"tes

o Na @ri5en Cl-HC3. Exchanger 0N@CE4

Important #or pHi regulation

/LCQ mem!er 0MM<4

2ses inwardl" directed Na

electrochemical gradient to dri5euphill entr" o# HC3. into the cell

o Cl-HC3. Exchanger

In5ol5ed in acid-!ase transport that

#xs independentl" o# Na %em!ers o# either /LCQ or /LC<V 0MM4

0/LCQ4 9nion Exchangers 09EM-9E.4

• 9EM = Important #or transport

o# HC3. into the 6C in thelung and out o# the 6C inperipheral tissues

• 9E< and .o Inwardl" directed Cl

gradient almostalwa"s dri5es out o#the cellR pla"s a rolein cell 5olumeregulation

0/LC<V4

• Pla" important roles inepithelial Cl and HC3.

transport

• multi#unctionalo 3ther 9nion Exchangers

Cl-Formate Exchange 0CFE4 and Cl-

3xalate Exchange

• Present in the apical

mem!ranes o# renal PC$• Important #or the secondar"

acti5e upta;e o# Cl Pendrin = mediates Cl-HC3. exchange

and transports I\which is important inthe th"roid gland

3rganic 9nion $ransporting

Pol"peptides 039$P4

• %em!ers o# /LC<M

• %ediates the upta;e o# !ile

acidsJ !iliru!in and the testsu!strate !romosulphthaleinin the li5er

Prostaglandin $ransporter 0P1$4

• %ediates the upta;e o#prostanoids

• 0eg, prostaglandins E< and F<a and throm!oxane <4

3rganic 9nion $ransporters 039$4

• /LC<<

• %ediate the upta;e o#endogenous organic anions!" exchange or #acilitateddi>usion

6egulation o *ntracellular *on Concentrations

(he #a+. Pump .eeps #a inside the Cell 7o5 and . High

Inhi!ited !" 3299IN ] Nai rises and K i #alls

Pla"s important role in generating the inside-negati5emem!rane 5oltage ] 0VmA4 in a t"pical cell

9ccomplishes in two wa"so .< 0NaK4 ] Electrogenic = causing outward

current o# positi5e charge across the plasmamem!rane

o 9cti5e K accumulation creates a conc gradient

that #a5ors exit o# K #rom cell through Kchannels

he tendency o# 4 to e-it through these channels, withunmatched negative charges le#t behind, is the main cause o# the

inside8negative membrane voltage. or this reason Na9sinwardly directed Na6electrochemical gradient allows passive

entry o# Na

o /odium 0Na4

Predominant in ECF at MQ7m% in Conc

1radient is maintained !" acti5eextrusion o# Na #rom cell !" Na-KPump

o Potassium 0K4

Q,7m% in ECFR predominant in ICF

a!out <7-. #old Its channel is inhi!ited such as a<+

and Am !ecomes less negati5e 0celldepolaries4

Cell Harness the Na Energ" #or $hree %a&or PurposesM, In certain epithelial cellsJ amiloride-sensiti5e Na

channels 0ENaC4 are largel" restricted to the apical orluminal sur#ace o# cell, Na-K pumps are restricted to the!asolateral sur#ace o# the cell, In this wa"Jtransepithelial Na transport ta;es place than a #utilerec"cling o# Na !ac; and #orth across a single plasmamem!rane

<, In e-citable cellsJ passi5e entr" o# Na entr" occursthrough 5oltage-dependent Na channels and pla"scritical role in generation o# action potential, Na is c"cledat high energ" cost across the plasma mem!rane #orimportant ph"siological purpose o# in#ormation trans#er

., Airtuall" e5er" cell in the !od" tissues uses Na gradientacross plasma mem!rane to dri5e the second acti5etransport o# nutrients and ions

Ca8% Pump and the #a+Ca Exchanger .eep *ntracellular Ca Four Orders o )agnitude 7o5er than EC Ca

• EC Ca ] Mm%J IC Mn% = Conc 1radient M-#old

• rought !" Aoltage-1ated Ion Channelo Ca<+ Pumps 0/E6C94 in 3rganelle %em!ranes

Ca pumps 09$Pases4 are present on

mem!ranes that surrounds 5arious ICorganelles such as sarcoplasmicreticulum and E6



9cti5el" se(uester c"tosolic Ca in IC

stores then released into thec"toplasm in !ursts as part o# signaltransduction process in response tomem!rane depolariation or humoralagents

o Ca Pump 0P%C94 on the Plasma %em!rane

%a&or route o# Ca extrusion

Pump itsel# is incapa!le o# this t"pe o#

#eed!ac; control !ecause it has a highKm #or Cai,

9s Cai risesJ the Ca !inds to a protein

called calmodulin which has a highanit" to Ca,

Newl" #ormed Ca-Ca% !inds to Ca

PumpJ lowers the pumps Km #or Ca i into the ph"siological range and thusstimulates Ca extrusion

Cai #alls = Ca-Ca% le5els IC #alls so Ca-

Ca% dissociates #rom Ca pumpJreturning pump to its inacti5e stateresulting Mn% at resting state

o Na-Ca Exchanger 0NC4 on Plasma %em!rane

For Ca eZux onl" when Cai rises

a!o5e normal le5els Important in restoring low Cai when

large inuxes o# Ca occur Contri!utes to the excita!le cells Aia Aoltage-1ated Ca Channels

*n )ost Cells Cl is )osdestly A$ove E"uili$rium BecauseCl 9pta:e $y Cl+HCO; Exchanger and #a-.-ClCotransporter Balances Passive Cl E<ux (hroughChannels

• Chlorideo OICFR ECFo Can passi5el" pass through mem!rane !ecause

o# the cells anion-selecti5e channelso VmA inside-negati5e mem!rane 5oltage

• Cl-HC3. Exchanger = most common pathwa" #or Clupta;e

•

Na)K)Cl Cotransportero mediate uphill Cl transporto Passi5e extrusion o# Cl through anion-selecti5e

channels in P% opposes Cl upta;e machanisms

• K)Cl Cotransporter

#a+H Exchanger and #a+4riven HCO; (ransporters .eepthe *ntracellular pH and HCO; A$ove (heir E"uili$rium

• 9cid Extruders = secondar" acti5e transporters that are

energied !" the electrochemical Na gradient across thecell mem!rane

o /ensiti5e to pHi changes

o /timulied when acidicR Inhi!ited i# al;alinied

ICFo Important Extruders

Na-@ri5en Cl-HC3. Exchangers 0M<4

Na)HC3. Cotransporters 0MM4

o Important 9cid/ecretors

A-t"pe H

H-K Pumps

• 9cid Loaders = !alance acid extrusion

=ater (ransport and the 6egulation o Cell /olume=ater (ransport is 4riven $y Osmotic and HydrostaticPressure 4iference Across )em$ranes

• 9lwa"s passi5e

• L3B FL2I@I$^ = L3BE6 H<3 PE6%E9ILI$^ due topresence o# phospholipids and long chains o# #att" acidswith #ew dou!le !onds

• /ingle water molecules can dissol5e in lipid !ila"ers _mo5e across cell mem!ranes at a low !ut ?nite rate !"simple di>usion

• Ease o# H<3 di>uses through lipid !ila"er depends onlipid composition o# !ila"er

929P36IN/ 09PM4

• /pecialie water channels that ser5e as a passi5e

conduits o# water transport

• Its presence increases mem!rane water permea!ilit"

• ollecting duct cells o# 3idney regulate the H2O

permeability o# their apical membranes by inserting 1$P2 water channels into their apical membrancesunder control o# 1(!ININ" and V1*OP("**IN

• Er"throc"tes or renal proximal tu!uleJ 9PM is alwa"spresent in mem!rane

Net @ri5ing Force

• < @ri5ing Forceso Chemical Potential Energ" @i>erence = water

conc dependent to the two sides o# themem!rane

o Energ" di>erenceJ per mole o# waterJ that

results #rom the di>erence in H^@63/$9$ICP6E//226E 0`H<3J pressure4 across the mem!rane

P = h"drostatic pressure Aw = partial morlar 5olume o# H<3

• 3/%3L9LI$^o concentration o# osmoticall" acti5e solutes

o 2NI$ osmoles);g o# H<3

• Colloid 3smotic Pressure)3ncotic Pressureo @i>erence in osmotic pressure that tends

pull!ac; o# uid

• 2ltra?ltrationo $he resulting mo5ement o# water out o# the

capillar" when h"drostatic pressure di>erenceexceeds the colloid osmotic pressure di>erence

Because o the Presence o *mpermeant #egativelyCharged Proteins =ithin the Cell 4O#A# FO6CES =ill7ead to Cell S5elling

Na-K Pump 9!sence = /BELLIN1

%odel NE19$IAEL^ CH961E@J I%PE6%E9N$%9C63%3LEC2LE/

Physio - Chapter 5

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