LOH, DCT and collecting duct Flashcards
what are limits for the osmolarity of urine determined by
osmolarity of the renal medulla
what is the loop of henle
juxtamedullary nephrons drop down into the renal medulla and then return to the cortex
characteristics of descending limb of LOH
lacks ion pumps
expresses lots of aquaporins
very permeable to water
permeability of thick and thin ascending limb of LOH
not permeable to water
what does active transport of ions out of the thick ascending limb lead to
osmotic transport of water out of the descending limb
2 steps in the loop of henle
static effect
fluid flow
what is the static effect
active transport if solute out of ascending limb to make interstitial space hyperosmotic and draws water out of descending limb making filtrate more concentrated
what is fluid flow
as filtrate is continually produced, new tubular fluid enters the descending limb and pushes the fluid at higher osmolarity down the tube
effect on osmotic gradient as static effect and fluid flow steps repeated
steadily multiplies down the tube
what is the capillary network surrounding the juxtamedullary LOH called
vasa recta
function of the vasa recta
supply oxygen and nutrients to the medulla
where does the vasa recta run
parallel to the limbs of the LOH
blood flow in the vasa recta
blood flows in opposite direction to the filtrate and hairpin loop slows blood flow down
components of the counter-current multiplier
specialised peritubular capillaries (vasa recta)
loop of henle
what allows urea to escape the collecting duct and be recaptured by the descending LOH
urea channels in the medulla
