transport of solutes and water Flashcards
what separates the intracellular fluid from the extracellular fluid
cell membrane
what is ECF (17L) composed of, order in highest % of ECF
interstitial fluid ,blood plasma,and trans cellular fluid
what is the hematocrit
fraction of blood volume that is occupied by (RED BLOODCELLS) erythrocytes, leukocytes and platelets
ICF/ ECF rich or poor in K Na and Cl
ECF rich in Na and cl
ICF rich in K
what separates the intravascular and interstitial compartments?
capillaries
infant men women in order from %TBW
infant men women
Total-body water (TBW) Intracellular fluid (ICF) Extracellular fluid (ECF) Interstitial fluid Plasma (PV) Transcellular fluid Blood (BV) which of these have same typical volume in L and same % of BW or ECF
plasma and transcellular
all have same %, except for TBW (men have more)
Why does a female has lower percentage of TBW
more adiopose tissue, fat cells have lower water content than muscles
what is the 3l extracellular of blood volume(6l)
plasma volume
Why does transcellular fluids differ geatly in composition from both each other and plasma?
they are secreted by different epithelia.
main difference between plasma and interstitial fluid? why and effect
plasma proteins, cannot equilibrate between capillaries walls. plasma proteins can affect distribution of solutes beacause of the volume they occupy and electrical charge they carry.
what would be a more meaningful unit for plasma composition of ions (e.g., Na + , K + ) in units of milliequivalents (meq) per liter of plasma solution
milliequivalents per liter of protein-free plasma solution
is the cation/anion concentration of the protein-free solution of the interstitium lower or higher than plasma concentration and why?
cation 5% lower
anion 5% higher
because negative charge of the plasma proteines retains the cations because of its negative charge.
proteins and lipids occupy ..% of total plasma volume
7%
do the volume and proteine charge corrections cancel each out?
for cation yes (0,95/0,93)
for anions no (1.05/0,93)
Δũ X=0 means?
that X is in equilibrium
Name two special cases for equilibrium state
- chemical and electrical both 0, so concetration of X is same on both sides of membrane and when X is uncharged or when charged, voltage difference must be 0.
- nether the chmical nor the electrical term are zeo but must be equal but of opposite sign.
If in equilibrium net driving force is negative, what will hapen to cations and anions
cations will enter the cell
anions will leave the cell
name three factors that make up the permeability coefficient of X
- partition coefficient; the better X can dissolve membrane lipid
- diffusion coefficient; X moves more readily when inside the membrane
- the membrane thickness
by what are the pathways for some ions and hydrofiele solutes formed
integral membrane proteins
name three types of pathways formed by membrane proteins
a pore that is always open
a channel that can be gated
a carrier that occludes a particle in its compartment
what membrane protein include virtually al ion channels, such as the ones that allow Na + , Cl − , K + , and Ca 2+ to cross the membrane ?
channel
How are large-size pores found in the outer membrane of gram-negative bacteria and mitochondria called?
Porins /porinen
How do cytotoxic T lymphocytes kill their target cells
by the release of monomers of a pore-forming protein called perforin.
what is the classic and alternative pathway (bacteria)
classic= binding of antibodies to an invading bacterium alternative= presence of native polysaccharides on bacteria, both trigger the complemnt cascade
what is the cascade of reactions triggered by alternative or classic pathway called?
complement cascade
what is the final component of the complement cascade
the pore made up by monomers of C9
How are the plasmamembranes channels called just large enough for water and in mammals small molecules?
aquaporin
name a technique to measure the Vm of a bigger cell
microelectrode
what 2 techniques are used to measure the Vm of a smaller cells like erythrocytes or organelles.
2 spectroscopic techniques: labeling the cell or membrene with an appropiate organic dye and monitoring the absorption of the fluorescence of the dye.
use cells that express genetically engineered voltage-sensing proteins that have been coupled to a modified version of the jellyfish green fluorescent protein (GFP
.
Skeletal muscle cells, cardiac cells, and neurons typically have resting membrane potentials of approximately A to A mV; smooth-muscle cells have membrane potentials in the range of B; and the V m of the human erythrocyte is only about C. However, certain bacteria and plant cells have transmembrane voltages as large as D
Skeletal muscle cells, cardiac cells, and neurons typically have resting membrane potentials of approximately −60 to −90 mV; smooth-muscle cells have membrane potentials in the range of −55 mV; and the V m of the human erythrocyte is only about −9 mV. However, certain bacteria and plant cells have transmembrane voltages as large as −200 mV.
the term ( V m − E X ) is often referred to as…
driving force
what is the difference between reciprocal synapses and rectifying synapses
reciprocal can pass electric current in both directions and other only in one direction
how much % of the body is made of water
male female infant
60% male
50% female
65-75% infant
why doe females have less TBW %?
because more adipose tissue, and fat cells have lower water content
how is hematocrit determined?
centrifuging blood that is treayed with an anitcoagulant / antistollingmiddel )and measuring the fraction of the total volujme occupied by these cells.
what is interstital fluid and perecentage of ECF
75%, outside the intravascular compartement
what is transcellualr fluid?
fluid trapped in spaces surrounded by epithelial cells
what kind of fluid is synovial fluid and cerebronospinal fluid?
transcellular fluid
where is the cation concentration higher and where the anion ? explain (intersitium and plasma)
cation concentration is higher in plasma, because proteins cant move through capillary wall (and proteins are negatively charge)
anion are expelled by cations so anion concentration is higher in interstium. (both 5% higher )
is osmolity different for the fluid compartments?
no
what is bulk electroneutrality
the number of positive and negative charges in the overall solution must be the same.
what is the anion gap
the difference between cations and anions
formula anion gap:
Na-(cl+HCO3)
what force is the electrochemical gradient
driving force
What is noncoupled transport?
movement of X is not coupled to the movement of another solute or to any chemical reaction (ATP)
What is unidirectional flux?
movement of X across membrane in one or the other direction
net flux is?
the algebraix sum of the two unidirectional fluxes.
When is X at equilibrium
when there is no net flux
what is a steady state of X
both driving forces on X are constant with time.
is equilibrium steady state?
a form of steady state.
what is this called (ψ i − ψ o )
Vm
what is the electriocehmical potential energy difference for X when at equilibrium?
0
What are the two ways X can be at equilibrium?
- when both chemical and electrical term is 0.
2. both are not 0, but of opposite sign.
Net driving force in volts?
Vm-Ex
What is Vm
-60mV
What wil cation and anions do when the net driving force is negative?
CATION WILL ENTER THE CELL
anions will leave the cell
What are the only to thing you need to know to understand the overall energetic s of X transport
that it is passive
and the drivving force Δũ X
what is the kinetics of transport of X
the rate
what is the flux ?
(Jx) how fast X moves
what is the unit of Jx
moles/(square centimeter ⋅ second)
what is the partition coefficient?
how easy X can dissolve through a membrane lipid
what is the diffusion coeffiecient?
how readily X moves once in the mebrane
is the flux greater if ifference in [X] between the two sides of the membrane increases
yes
what is this formula called
Jx-Px([X]-[X]i)
ficks law
What is Px in Ficks law called
proportionality constant
is the net flux proportional to the concentration difference or ratio?
(not the ratio [X] o /[X] i , but the difference [X] o − [X] i )
what are carrier
a protein pathway, equipped with at least two gates that are never open at the same time, with compartment that contains binding sites for a solute.
is the nuclear pore complex passive or active transport
both
what is AQP1 (what polymere.
a tetramer
Each monomer (AQP1) consist of ?
8 helicles
6 larger
2 shorter
is actrive transport uphill or downhill?
uphill
what is secondary active transport?
uphill moevemnt of the solute couppled to the downhill movemnt of on or more other solutes.
what the β subunit (na-k pump) responsible for?
essential for proper assembly and membrane targeting
what is the α subunit,
10 transmembrane segemnts, which is the catalytic subunits that mediates transport
what does quabain do
binds to E2-p blockoing the pore, unfuctional na-K pump
what is electrogenic pump example
net extrusion of one postive charge from cell
Na-K pump
what are cardiac glycosides, 2 examples
blockers of NA-K pump, ouabain, digoxin
where do cardiac glycosides bind?
extracellular side, E2-P
what happens when ATP on the Na-K pump phosphorylates?
ADP leaves, 3 Na are occluded. and deoccludes later.
what happens to the Na-K pump when the acylphosphate bond hydrolyses?
it occludes the 2 K
what happens if ATP binds to the NA-K pump
First, the pump becomes deoccluded, so that the K + -binding sites now communicate with the intracellular solution. Second, the K + affinities of these binding sites decrease.
what is the stoichiometry of the pump?
three Na + to two K +
