Excretion
A) Kidney Structure
Detailed Kidney Animation + Quiz http://www.sumanasinc.com/webcontent/animations/content/kidney.html
B) Dialysis
Dialysis mechanism Animation http://www.kidneypatientguide.org.uk/HDanim.php
C) Additional Concepts
Counter Current Multiplier" Video http://www.youtube.com/watch?v=XbI8eY-BeXY