Loop of Henle (magnified)
Ansa nephroni
UrinaryOrgansWhole body
- What it is
- Hairpin loop dipping into the medulla: a thin descending limb, a thin ascending limb and a thick ascending limb that climbs back to touch its own glomerulus (macula densa).
- Function
- Builds the salty medullary gradient by countercurrent multiplication: the descending limb lets water out, while the water-tight thick ascending limb pumps out NaCl (NKCC2 transporter).
- Size
- Reaches up to ~1 cm into the medulla in juxtamedullary nephrons.
- Clinical note
- Loop diuretics such as furosemide block NKCC2 in the thick ascending limb and cause a large diuresis.