Stuff inside your body (but not really)

The above are a bunch of dudes I doodled in my biology notebook several years back. They're supposed to represent several body functions.
Today, I refurbished them all nice and neat!

Internal security?... Ears... Brain... Nose... Digestion... Allergies?... Security... Eyes... Nerves

Drawn using:
No. 2 pencil (both)
Colored pencils (2)
0.5 mm pilot pen (2)