What are the four parts of the nervous system?

Answer 1

You could define the 5 major parts of the nervous system by saying they are:

the central nervous system, and the somatic, sympathetic, parasympathetic and entericnervous systems.

However, a better way of describing the parts of the nervous system is to

divide it into two main parts and then sub-parts:

the main parts:

the Central Nervous System (CNS, brain & spine),

and the Peripheral Nervous System (PNS, all the nerves and neurons outside the brain and spine).

Then the peripheral nervous system is divided into

the somatic nervous system (nerves which control the voluntary muscles) and

the autonomic nervous system (nerves which control visceral functions or organs like the heart or stomach);

and the autonomic nervous system is itself divided into the

sympathetic (fight-or-flight emergency response),

parasympathetic (relaxation),

and enteric (digestive) nervous systems.

Answer 2

I only know of 2..

The cerebrum and the cerebellum

Answer 3

There is the central nervous system and the peripheral nervous system and then you would have certain subsets of those systems.