The Loop of Henle Flashcards
what is the function of the Loop of Henle
to generate a cortico-medullary solute conc. gradient
describe the fluid flow of the Loop of Henle
a countercurrent flow, due to opposing flow of the 2 limbs(ascending and descending)
what do the Loop of Henle and vasa recta establish in the interstitial fluid, and what does this allows
a hyperosmotic medullary interstitial fluid, allows a hypertonic urine to be formed
describe the movement of water and NaCl(salt) in the descending limb(DL)
NaCl not reabsorbed
Highly permeable to water
describe the movement of water and NaCl(salt) in the ascending limb(AL)
NaCl are absorbed in the full length
Relatively impermeable to water
describe why there is no/very little reabsorption of water at the ascending loop
the tight junctions of the thick part of the AL are too tight and don’t allow osmosis of water
how is salt(NaCl) reabsorbed in the ascending limb at the apical membrane
by the Na/K/Cl triple co-transporter pump
describe how the osmolarity of the filtrate changes as it goes down through the descending loop of Henle
becomes more osmotic(more conc.) as it descends the limb as water is reabsorbed due to interstitial hyperosmolarity, but salt doesn’t follow and so filtrate more conc.
describe how the osmolarity of the filtrate changes as it goes up through the ascending loop of Henle
it becomes less osmotic(lower conc.) as it ascends the limb as NaCl is reabsorbed into the interstitial fluid, making it more hyperosmolar and diluting the filtrate as water cannot follow
describe the osmolarity of the filtrate compares to interstitial fluid as it leaves the proximal tubule and when it enters the distal tubule(ie after Loop of Henle)
leaving proximal = iso-osmotic
entering distal = hypoosmotic
describe how the osmolarity of the interstitial fluid changes as you go down the medulla, ie towards the renal pelvis
it gets more hyperosmotic as you go down
describe why the function of the Loop of Henle is useful
allows kidney to produce urine of different volume and conc. according to amounts of ADH
where are the vasa recta found
they are the single capillary that follows the juxtamedullary nephrons, which have a longer Loop of Henle
describe the role of the vasa recta in the countercurrent system
allows movement of NaCl and water, so as descends with Loop of Henle, loses water gains salt, and as ascends gains water loses salt, due to hyperosmotic interstitial fluid
describe the absorption and permeability of the vasa recta for NaCl and water
“leaky”, so allows water diffusion and NaCl movement
