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by Greg Crowther


Epo, epo ... epo!
(Epo, epo ... epo!)
Kidneys talk to ... marrow!
(Kidneys talk to ... marrow!)

The marrow ... has cells that form erythrocytes,
Which are designed just right
To carry O2.
But if ... production goes too rapidly,
Then blood viscosity
Could slow the flow-through.

Epo, epo ... epo!
(Epo, epo ... epo!)
Canít be too high ... or too low!
(Canít be too high ... or too low!)
Oh no!


A short song about erythropoietin ("epo" for short) written for Biology 220 at the University of Washington. Questions: (1) What does "kidneys talk to marrow" mean? (2) By what other common name are erythrocytes known? (3) Where in the erythrocytes does the oxygen bind? (4) Why does the song claim that epo "can't be too high ... or too low"? Answers: (1) Epo is a peptide hormone, released from the kidney, that stimulates production of red blood cell (erythrocyte) precursors in the bone marrow. (2) Red blood cells. (3) To hemoglobin, the main protein present in erythrocytes. (4) A low density of red blood cells (i.e., low hematocrit) leads to anemia, but an elevated density results in highly viscous, sludge-like blood, as experienced by certain cyclists in the early days of blood doping. Thus, as with many physiological variables, it is dangerous for erythrocyte density (and thus epo levels) to be either too high or too low.

Other Files

MP3 (demo)

score (with melody play-back)