Countercurrent Flow

by Greg Crowther

This is a brief musical tribute to one of the most beautiful physiological mechanisms of all time -- countercurrent flow -- which can be found in the far-flung examples listed in the lyrics below.

Flow, countercurrent flow.
Two streams side by side; they come and go.
The one takes from the other; a gradient makes it so.
Oh, countercurrent flow.

The gills of a fish; the loop of Henle of a mammal.
The tongue of a whale, and the nose of a camel.
Oh, oh, oh, oh,
Oh, countercurrent flow.

• karaoke (by Monty Harper)

• MP3 (by Monty Harper)

• music video

• 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 the definition of a countercurrent flow?

(2) What kind of flow is the opposite of countercurrent flow?

(3) What is transferred via countercurrents in each example listed?

(4) What is the advantage of a countercurrent flow system over a concurrent flow system?

(5) Gas exchange in bird lungs occurs via an anatomical arrangement that is neither countercurrent (as fish gills are) nor concurrent (as mammalian lungs are). What is the bird-lung arrangement?

(6) "Loop of Henle" is an eponym, i.e., a structure named after a person. Eponyms are being phased out of anatomy. What is the current preferred term for "loop of Henle"?

(7) Considering the specific content covered by this song, is there anything important that is missing, unclear, or misleading? If so, what?