Where Osmolarity is High

by Greg Crowther

This is a song originally written for Biology 352 at UW-Bothell. 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.

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'!

• MP3 (demo)

• sheet music (with melody play-back)

Songs like this one can be used during class meetings and/or in homework assignments. Either way, the song will be most impactful if students DO something with it, as opposed to just listening.

An initial, simple follow-up activity could be to answer the study questions below. A more extensive interaction with the song might entail (A) learning to sing it, using an audio file and/or sheet music as a guide, and/or (B) illustrating it with pictures, bodily poses, and/or bodily movements. The latter activity could begin with students identifying the most important or most challenging content of the song, and deciding how to illustrate that particular content.

(1) What is osmolarity? How does osmolarity influence the diffusion of water?

(2) What is the meaning of the line, "if the pores are in position"?

(3) What are "aquaporins in the duct"?

(4) What is ADH?

(5) What is the meaning of the line, "it's water that you're missin'"?

(6) Besides "the duct," where else are aquaporins located? Are those other aquaporins regulated by ADH?

(7) Explain how conservation of water in mammals requires both the loop of Henle and ADH.