Chapter three deals with several interesting topics: transmission of neurons inside of the brain, the functional roles inside of the brain and how they are related to specific parts of the body, and human genetics. Each of the lobes of the brain are described in detail, as well as each component of the central nervous system.
The concept that I found most intriguing in this chapter is the idea of lateralization in the brain--that is, the separation of cognitive functions to one hemisphere of the brain or the other. What was really interesting, though, is the idea that a person may be able to fully function with only one hemisphere in the brain. Page 112 talks about the ability for children that undergo such a surgery--that is, removing half of their brain--are sometimes able to teach, in essence, the remaining hemisphere of the brain how to perform the functions performed by the removed hemisphere. This was a shocking, yet cheerful, thing to read about.