Solute Transport Flashcards

1
Q

Brownian motion

A

E required for simple diffusion

move down concentrtion gradient

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2
Q

factors in simple diffusion

A

partition coefficient - how well substance moves into lipid from water (dx)

D- diffusion coefficent - how well moves when in the membrnae (inversely propotional to MW, viscosity of medium)

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3
Q

Fick’s Law

A

flux (j)

Permeability coefficient x driving force

P = D x A x 1/X

molecules that cross certain area/second = flux

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4
Q

basolateral membrane

A

faces blood (capillaires)

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5
Q

apical membrane

A

faces lumen

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6
Q

antiporter

A

2 ions in opp direction (simple diffusion)

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7
Q

symporter

A

i.e. glucose and Na+

secondary active transport

co transport

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8
Q

channel

A

has gate

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9
Q

pore

A

has no gate (H2O)

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10
Q

Na/K ATPase

A

primary active transport

requires energy to oppose concentration gradient

[Na] - higher onoutside

[K] -higher on inside

pump Na out and K in

requres ATP

on basolateral membrane of every epithelial cell

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11
Q

paracellular transport

A

in tight junctions

mediated by claudins

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12
Q

Na+-glucose transport

A

secondary active transport

Na/K transport pumps Na out wiht ATP (basolateral side)

Na+/glucose (SGLUT) pumps glucose in

Na+ gradient is potential energy

Glucose leaves through GLUT 2 - not dep on gradient/E = through basolateral side

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13
Q

Amino Acids into cell

A

secondary active transport - also linked to Na+ gradient

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14
Q

Carrier mediated transport

A

fasterthan diffusion

can saturate

acts as enzyme

diff from ion channels (which have gates)

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15
Q

K+/H+

A

ATPase - responsible for gastric acid secretion

active

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16
Q

Na+/H+

A

exchange

responsible for intracellular pH and Na exchange

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17
Q

Cystinuria

A

for cysteine - transports Cystine in for reabsorption (apical membrane) - transporter

if mutations = urine has 100% of cystine - stones (poorly soluble)

SLCs

drink water or bowel as urater

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18
Q

CDME

A

analog for cystine

slows crystal growth

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19
Q

Water composition of humans

A

60% - varies based on muscle mass (less mucscle mass = less water)

muscle –> intracellular space

distribution –> blood volume (BP) and cell volume (cell function)

20
Q

water - intracell v extracell

A

2/3 intracellular

1/3 extracellular

21
Q

water - extracellular distribution

A

3/4 intracellular (between cells, vessels)

1/4 intravascular (plasma - 75% is in veins) )

22
Q

plasma composition

A

93% is water, 7% is proteins and lipids

23
Q

intracellular osmole

A

K

solute that keeps water in that compartment

24
Q

extracellular osmole

25
intravascular osmole
plasma proteins
26
effective osmole
i.e. glucose in the absence of insulin can't cross any membrane! water always goes in that direction
27
ineffective osmole
i.e. urea (except in kidney) always movesacross membrane
28
permeant solutes
can only lead to transient changes in volume
29
impermeant solutes
can influence cell volume at steady state
30
osmolarity
osmoles/L same as osmolarity in dilute fluids
31
osmotic coefficient
osmotic coefficient - if not perfectly ionized i.e. .93 for NaCl
32
iso-osmotic
same total number of particles same osmolarity 1 M glucose, 1 M urea, .5 M NaCl all solutes matter
33
isotonic
same number of osmotically active particles same osmotic pressure .5 NaCl, .333 CaCl2, NOT 1 M urea non penetrating solutes mater ONLY
34
NS + D5W
roughly isoosmotic (same number of mosm/kg-water) NOT isotonic: due to effects of insulin - glucose moves into cells and it is NOT an effective osmole under that coldition (NaCl is effectively extracellular due to Na/K-ATPase)
35
hypotonic solution
if put cell in it will swell/yse pressure ECF \< presure ICF
36
isotonic solution
cells stay the same P of ECF = P of ICF
37
hypertonic solution
cells will shrink P of ECF \> P of ICF
38
Cell response in hypertonic ECF
usually cell will shrink and water will leave cell pumps salts in (NKCC) - Na+, Cl- x2, K+ so not as much water will leave
39
cell response in hypotonic solution
cell will swell swelling activates K chanels and K diffuses OUT down electrochem gradient osmoles leave cell and water follows
40
paracellular transport
passive but selective variable and regulated through tight junctions H2O through paracellular space - in response to osmolarity - Na leaves and H2O neaves
41
Leaky epihelia
large volume reapsorption - jejumum, proximal tubule
42
tight epithelia
for concentrtion excreta - collon and collecting duct
43
ECF volume
determined by total body Na+ content
44
osmolarity
determined by total body water content
45
ECF Na+ content
in mmoles = [Na+] x ECF vol (L) = osmolality/2 x ECF vol ()
46
total body osmoles
[osm] X TBW (L)
47