Talbot- Osmosis and Diffusion Flashcards
define diffusion ?
the movement of a solute suspended or dissolved in an aqueous solution down it’s concentration gradient due to random thermal movement .
In diffusion the solute moves from ?
from high concentration to low concentration , no energy input require
what is the physical factors /properties for diffusion ?
no energy input needed
efficient ( rapid) only over short distance
what is the rate of diffusion (Jx) is proportion to ?
Proportional to the concentration gradient
inversely Prop. to distance L^2
( the greater the distance between 2 points the greater the time it take to diffuse .
how we measure the rate of diffusion ?
as A FLUX RATE across the membrane
how diffusion happened across the membrane ?
by simple diffusion , and Facilitated diffusion
what is the difference between facilitated diffusion and simple ?
simple : solute moves from high concentration to low concentration .
Facilitated : solute moves from high concentration to low concentration DUE to specific transporters (protein Mediated )
what is the flux rate?
how much of something moving over time .
Jx=dQx/dt ( change in quantity / change in time )
what is the difference between influx, Efflux , net flux ?
Influx (Jin): movement of solute into a chamber /cell/compartment , Efflux (Jout) : movement of a solute out net flux ( Jnet ) difference between (Jin)-(Jout)
what is unidirectional flux ?
it is the net flux
Jnet =Jin - Jout
All solutes and systems want to move towards what ?
Their own equilibrium , no matter what other solutes are present or what is their concentration are .
does the living body moves towards equilibrium ?
NO , living body is an open system so it works to maintain a steady state .
what is Fick’s equation ?
J= D A (dC/dX) (dC/dX) concentration gradient A area J rate of diffusion ( moles /second) D is diffusion coefficient or can be P ( when it is experimentally calculated)
what is D proportion to ?
temperature , 1/viscosity ,
1/ molecule size of solute
define Osmosis ?
diffusion of water , moving from low concentration of solute to high concentration of solute .
how much water in our body ?
45%-70% of body mass
Men 60%, women 50%
a man weight 70 Kg calculate the total body water TBW ?
men has 60% water so .60x70=42kg water
what are the compartments of TBW total body water ?
all the water in the body ,
TBW =extra cellular fluid ( ECF) 34%
+ICF 66% Intracellular Fluid.
what is ECF ? what are the compartments of it ?
Extracellular fluid : all fluid outside of cells
ECF= 25%vascular +75% ISF ( interstitial fluid )
name the three body fluid compartments ?
Intracellular fluid
interstitial fluid
vascular fluid
Define Osmolarity ? Molarity ?OSMOLALITY ?
Osmolarity : (osm/L) measure solute concentration , number of osmoles of solute particles per liter
Molarity : moles /liter
OSMOLALITY ? osm/Kg water , measure of the osmoles of solute per Kg of solvent
Define Osmotic pressure (pi)? and what it is similar to ?
Pulling force that attract water towards more concentrated solution.
similar to hydrostatic pressure ( P=n/V)RT
Pi= (osmol/L) RT
what is the osmolality of human fluids ?
290 mOsm
water is at what osmotic level across most animal cell membrane ?
Osmotic equilibrium
protein in plasma is more , less or equal to ISF ?
more in plasma
what is predominant cation in ICF ?
K+ to balance proteinn - in ICF
is there any ionic concentration different between all three compartments ( ICF, plasma , ISF) ?
yes , however they have effectively identical osmolarties.
what is difference between Osmolarity and Tonicity ?
Osmolarity : is actual number of particles dissolved in solution represent a potential for water to move across a membrane.
Tonicity : actual response of cells or tissues immersed in a solution , represent the FLUX OF WATER ACROSS A MEMBRANE
what does that means when the cell is
ISO-osmotic, Isotonic environment ?
have no net flux of water because the intracellular and extracellular solutions are iso-osmotic
what does that means when the cell is
Hypo-osmotic, Hypotonic environment ?
the environment is hyp-ismotic relative to the cell , cell is HYPER-osmotic relative to the environment, cell swell
what does that means when the cell is
hyper-osmotic, hyper-tonic environment ?
the enviroment is hyper-osmotic to cell , and the cell is HYPO osmotic to the environment , cell shrink
cell in its surrounding solution is iso-osmotic does has to be isotonic?
NO , it depends on the presence /absence of osmotically active solute
what is osmotically active solute ?
the one that is impermeable or has limited permeability
what solutions would be isotonic to ICF of RBC?why ?
145 mMNaCL, 290 sucrose , 95mM MgCl2, 289mM Na+ and 1mM proein
they are Impermeable across the cell membrane , so the solution will be isotonic or isomotic.
what solutions will permeable to the cell membrane ?
Urea, ethanol , and they will be hypotonic to the cell.
the contribution of a solute to tonicity depend on what ?
its membrane permeability
which part of the cell is sensitive to any small change in the number of the solute ?
IntraCELLULAR volume of the cell is small, it does not take much of a change in total number of solutes inside the cell to lead to changes in concentration and osmolarity.
if substance stay on only a particular compartment what it is the volume ?
Volume ( L) = amount (g) / concentration ( mg/L)
if portion of the substance is excreted or metabolized what is the volume ?
volume ( L) =( amount - excreted) / concentration
how to measure Plasma volume ?
all the water in the blood , use albumin, or evans blue dye to bind to serum protein
