Countercurrent multiplier

Countercurrent multiplier (CCM)

using energy to generate an osmotic gradient that enables you to reabsorb water/NaCl and produce conc. urine

1. CCM starts by

flowing down D limb (of L of H)

the D limb has aquaporins but need an ____ ____ for H₂O movement

osmolarity gradient

osmolarity gradient

# of things/volume (n/V)

lumen is inside of

nephron (L of H in this case)

when lumen osm = IF osm

no change in osm (no water movement)

2. up A limb where NaCl pumped into IF which causes

• lumen osm dec.

• IF osm inc.

3. New flow down D limb where after step 2

lumen osm does not equal IF osm

After the osmolarity gradient changes, the lumen osm for the D limb

inc.

Lumen osm. inc. after step 3 b/c water = __ in osm eq

volume

lumen osm. increasing also makes sense b/c diffusion and not ___ is occurring from the movement of H₂O

transport

The CCM process ____ with new ____

repeats, flow

the osm gradient __ for the A limb

dec.

the osm gradient inc. for the ____ also

medulla

the L of H is just the” ___” for the CD

set up

Collecting duct has a ______ gradient

through

through gradient

a gradual change in quantity

ADH is aka

vasopressin

if ADH is present during CCM it will result in _____ forming in the CD

aquaporins

aquaporins in the CD cause

inc. in osm in CD & concentrated urine

if no ADH

• no aquaporins will form in CD

• dilute urine (dec. in osm)

an inc in length of L of H and smaller renal pelvis causes _____ which is good for water ____ environements

inc OSM in D limb, lacking

a smaller L of H is great for animals in

water abundant environments

there is an ombre pattern of color for the nephron due to

change in osm

lighter color → darker color indicates

an inc. in osm