When The Milk Comes In

by Greg Crowther

This song briefly highlights the anatomy and physiology of two related processes that are both necessary for mammals to nurse their young: the secretion of milk from the cuboidal cells of the acini, and the ejection of the milk from the acini by myoepithelial cells.

CHORUS:
When the milk comes in
To feed a newborn kid,
The acinar cells
Are secreting it!
And when the milk’s let down,
All the ducts get filled
When the acini squeeze,
So the kid can swill!

A neurohormone reflex is set in motion by the infant’s suction.
The hypothalamus will signal the pituitary gland.
Prolactin is released to generate a surge in milk production,
And thanks to oxytocin, the milk becomes ejected on demand!

CHORUS

• sheet music

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) Which specific structures secrete prolactin and oxytocin?

(2) What is an acinus?