The brain with the spinal cord and network of nerves controls information-related current fluxes throughout the body. This system regulates both voluntary actions such as walking, reading, and talking, and involuntary reactions such as breathing and digestion. The four principal sections of our brain are: the brain stem, the diencephalons, the cerebrum (two hemispheres), and the cerebellum.

The cerebrum (the Latin word for "brain") is the biggest part of the brain; it constitutes about 90% of the brain's weight. There are several information-specialized areas in the cerebrum where specific impulses from different sensory organs are transmitted. Part of cerebrum is responsible for spoken and written languages, Motor areas control muscle movements including hand muscles for writing and eye muscles for physical movement necessary for reading. There is an area translating thoughts into speech, coordinating the muscles involved into the speaking process. 

 (to be continued)