miscellaneous slide











Henle's Water Music

by Greg Crowther


[Part 1]

Where osmolarity is high
In the renal interstitium,
That's where water will diffuse
If the pores are in position.

So when ADH is high,
And it's water that you're missin',
Aquaporins in the duct
Lower water loss from pissin'!

[Part 2]

(100, 300; 100, 300)
(300, 1200; 300, 1200)
(100, 300; 100, 300)
(300, 1200; 300, 1200)

Countercurrent multipliers, y'all -- (100, 300)
Bird and mammal kidneys got 'em. (300, 1200)
A small gradient 'cross the lumen wall. (100, 300)
A large gradient, top to bottom. (300, 1200)

Salt's extracted from ascending limbs; (100, 300)
Water exits while descending, (300, 1200)
Sparing all of us a fate so grim: (100, 300)
Urination never-ending! (300, 1200)


This is a two-part song originally written for Biology 352 at UW-Bothell. The parts can be used separately or together. The song covers the mechanism by which water is conserved in mammalian kidneys. In brief, the nephron's loop of Henle maintains an osmolarity gradient such that, when pre-urine travels down the collecting duct, water is drawn out of the collecting duct into the interstitial fluid and reabsorbed by the blood.

The rising melody of the lines "Where osmolarity is high" and "So when ADH is high" provides musical reinforcement of the idea that, in the scenario of the song, these parameters are indeed high.

Questions: (1) What is the meaning of the line "if the pores are in position"? (2) What is the meaning of the pairs of numbers 100/300 and 300/1200? (3) What does ADH stand for? (4) Explain how conservation of water in mammals requires both loops of Henle and ADH. Answers: (1) Water can only diffuse out of the collecting duct if water channels -- aquaporins -- are present in the membranes of the cells lining the collecting duct. (2) These numbers are osmolarities given in units of milliosmolar (mOsm). 100/300 represents the relatively small osmolarity gradient that can be generated between the nephron lumen (e.g., 100 mOsm) and the interstitium (e.g., 300 mOsm). 300/1200 represents the much larger osmolarity gradient between the "top" of the interstitium (in the cortex; 300 mOsm) and the "bottom" of the interstitium (deep in the medulla; 1200 mOsm). (3) ADH is antidiuretic hormone. (4) The loop of Henle sets up and maintains the osmolarity gradient that ultimately pulls water out of the collecting duct so that it is not lost in the urine. However, water's exit from the collecting duct depends on aquaporins, as noted above, which are made and inserted into the cell membrane in response to ADH.

Other Files

MP3 (demo)

score (with melody play-back)