Heart, Lungs, Brains, Veins, Liver

All right, I'll take a stab at it. The lungs are obviously the speakers, the veins the cabling, the heart the power amp, the brain the sources, which leaves only the liver to be the pre.

I'm thinking the liver would be whatever component wears out the quickest. 

The pre-amp is the Heart of any system. Start your system building here.
Happy Listening!

Well if the speakers are the lungs then the lower intestine and colon must be the subwoofer.
But I think the amp is the heart and the pre amp is the brain. 
Ears -antenna
liver-a/c conditioner
vascular-cables
feet-isolation
bones-rack
fingerss-remote
can’t figure what can be the source organs

I am jumping off here

Ha, some good ones theo! I was thinking more literally. For example, the power amp or pre amp being the heart is nice in the lyrical, romantic sense, but I was thinking of it in the sense of pumping power to the speakers (just as the heart pumps blood to the body. The speakers and the body do all the "moving"). Speakers "exhale" like lungs do. The sources being the brain, as both are where the musical ideas come from. An a/c conditioner as the liver is perfect, though!