Lecture 4 - Tubular function (LoH) Flashcards
what percentage does the PCT reabsorb?
65%
whats the flow like in ascending and descending pct
counter-current flow
why is the collecting duct important for urine
fine tune of diluting and concentrating the urine;
large or small volume of urine
what blood supply supplies the LoH
vasa recta
what aspect of the nephron determines the urine is diluted/concentrated
collecting tubule
what does high osmolality mean
concentrated filtrate
what does concentrated filtrate mean
the high amount of ions and low water concentrations
why are hyperosmotic medullary interstitium’s important
allows the kidney to concentrate the urine more
what is the osmolality like surrounding the collecting ducts? why is this ?
very high;
creates a corticomedullary gradient
what type of fluid moves from the PCT
isotonic fluid
what type of fluid moves to the DCT
hypotonic
what channels are and arent present in the ascending LoH. what does this mean?
Sodium and Chlorine channels;
no aquaporins;
that H20 wont follow the salts
why are there sodium and chlorine channels in the ascending LoH
to create the corticomedullaru gradient
what happens to the osmalilty in the DCT and why ?
is much lower;
due to the sodium channels and chloride channels kicking out ions into the interstitium
Which drugs act upon this channel and how?
loop diuretics - stops the channel from working, decreasing the corticomedullary gradient, therefore water doesnt leave out the collecting tubule, more diluted and increased volume of urine
Which drug acts upon this channel and what does this do?
loop diuretics;
channel is blocked, no movement of ions out the DCT, smaller corticomedullary gradient, water doesnt get reabsorbed in the collecting tubule, making you urinate more, diluted urine
