Outside the brain Edit

There are a bunch of layers of the head before you get to the brain:

Also blood vessels can go from inside the arachnoid trabeculae down through their own linings of pia mater and glial limiting membrane into the rest of the brain

The Brain Edit

It's about three pounds and runs on about 20 watts of power. That's like 4 night lights, a computer in sleep mode, a low-speed ceiling fan, a cfl light bulb, or a Nintendo Wii. A similarly powered computer takes more than a million times more power. It's a soft pudding; you could scoop it with a spoon. If you dumped it on the counter, it would flatten a bit like a jellyfish.

"If the human brain were simple enough for us to understand it, we'd be simple enough that we couldn't." - Moran Cerf

The brain is divided into two hemispheres on the left and right. Each hemisphere has three parts. The parts are in decreasing order of how recently they evolved (and the more recently evolved ones, higher up on the list, surround the ones below them in concentric spheres):