The Proximal Tubule and Reabsorption Flashcards
how much fluid is reabsorbed in the proximal tubule itself
about 80ml/min of filtered fluid is reabsorbed in the proximal tubule
describe the osmolarity of the fluid absorbed in the proximal tubule compared to the filtrate
it is iso-osmotic with the filtrate
what different types of carrier-mediated membrane transport are used to reabsorb molecules in the proximal tubule
primary active transport, secondary active transport and facilitated diffusion
where is Na+ absorbed in the nephron
everywhere except descending part of Loop of Henle
what transporter is involved in the reabsorption of Na+ in the proximal tubule at the basolateral membrane
Na/K ATPase
what transporters are involved in the reabsorption of Na+ in the proximal tubule at the apical membrane
Na/glucose cotransport, Na/amino acid cotransport, Na/H+ countertransport
describe how the net reabsorption of Na+ in the proximal tubules allows Cl- reabsorption
due to Na being +ve, Cl being -ve, Na drives movement of Cl- in same direction as it
what does the net movement of Cl and Na reabsorption in the proximal tubules result in
passive water reabsorption, as water follows salt(NaCl)
this is why no change in osmolarity of fluid, ie iso-osmotic
describe how glucose is reabsorbed in the proximal tubule
Na/glucose cotransport at apical membrane
facilitated diffusion at basolateral membrane
describe what the transport maximum(Tm) of a substance is
the maximum rate at which a particular substance can be absorbed
where does filtrate go after leaving the proximal tubule
the Loop of Henle
