Epithelial Transport Flashcards
At rest, the apical _____ channels are closed.
Cl-
What kinds of metabolic waste molecules are non-volatile?
urea and protons
_____ cannot maintain large energy gradients because solutes and water leak back across the epithelium through the pericellular shunt.
Leaky epithelia
In the lungs, ____ diffuses passively from blood to air.
CO2
How does someone get cystic fibrosis?
it’s genetic
How do the kidneys filter waste?
the epithelial cells lining the tubules reabsorb the things that it wants to keep (glucose, salts, bicarbonate, etc)
Each day the cells in an adult human produce about ____ of metabolic waste solute.
15 moles
What is Uremia?
urine in the blood
Functions of the kidney include excreting non-volatile metabolic wastes and _____.
regulating the composition of virtually all ECF solutes as well as water
By keeping the ______ concentration low, the Na/K pump provides the energy to drive a host of secondary transporters.
intracellular sodium ion
How are the metabolic waste solutes removed from the body?
fluid exits the lungs; the kidneys do the rest
Synonyms for _____ include serosal and peritubular.
basolateral
Where are water pumps located in the body?
they don’t exist
What is the defect in cystic fibrosis?
the Cl- channel is mutated, reducing the epi’s ability to secrete serous fluid, causing very thick mucous and infections
What does CFTR stand for?
Cystic Fibrosis Transmembrane Conductance Regulator
In general, epithelia engaged in _____ are leaky, while those epithelia doing the finishing work are tight.
massive transport of substances
A ____ transepithelial voltage would be measured in leaky tight junctions.
lower
By keeping the intracellular sodium ion concentration ____, the Na/K pump provides the energy to drive a host of secondary transporters.
low
In general, epithelia engaged in massive transport of substances are leaky, while those epithelia _____ are tight.
doing the finishing work
How are the GI tract epithelium transporters regulated?
they aren’t- they will absorb everything ingested
Water always moves passively down _____.
osmotic gradients
What is the equation for transepithelial potential difference (transPD)?
TransPD = Vm (Basolateral) – Vm (Apical)
How does cholera toxin work?
it locks open the Cl- channels, causing a massive efflux of fluid from the cell
Water always moves _____ down osmotic gradients.
passively
