First of all, there is a hard bone just under the skin of the head. This bone is called the skull, and inside this skull is the brain. However, the brain is not bare and naked; rather, it is enclosed in three sheets of wrapping paper. From the outside, the brain is covered by three membranes called the dura, arachnoid, and soft membranes.
First, the brain is surrounded by small blood vessels that run like a web. These blood vessels carry oxygen and nutrients to the brain, and then dispose of carbon dioxide and waste that is no longer needed in the brain.
The brain is packed with nerve cells.