You've Got Edema!

by Greg Crowther

The idea that capillaries drop off oxygen and pick up carbon dioxide is straightforward to most students. Less easy to grasp is the fact that fluid also exits and enters capillaries according to the balance of hydrostatic and osmotic pressures. While this movement of fluid might seem unimportant, disruptions can lead to an accumulation of fluid in the interstitial space, i.e., edema.

Hydrostatic and osmotic pressures
Dictate where fluid flows.
From the capillaries, fluid leaks out;
Then back in it goes.

Overall, there's a transfer of fluid
To interstitial space.
But a network of lymphatic ducts
Drains the excess from that place,
Or else, worst case,

You've got edema!
You've got a edema!
Like a flood for FEMA!
You've got edema!

• 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 are hydrostatic and osmotic pressures?

(2) What is interstitial space?

(3) What do the lymphatic ducts do with the fluid they take away?

(4) What is FEMA and what, if anything, does it have to do with this song?