The nervous system of animals is the communication system of the body with the brain being the hub. It receives messages and returns corresponding signals.
The central nervous system of most animals consists of a brain, spinal cord and neurons. Some simple animals function without a brain like invertebrates that use a reflex system.
The brain composition is primarily water and lipids. Most animal brains consists of several parts. The brain stem controls the reflexes and automatic functions of the body like breathing and muscular movement. The cerebellum coordinates the movement of the arms and legs. The hypothalamus works with the pituitary gland to control feelings, such as anger and sexual stimulation, behavior and the body’s thermostat. The cerebrum or the cerebral cortex is the center of thought, memory and processes the sensory information.
The spine is the bones of the back that form a protective channel called the spinal canal. The spinal cord runs through the spinal canal. It is much like a tree trunk with branches running throughout the body.
There are two basic types of nerve cells known as neurons in the body. The afferent neurons send the signal to the brain and efferent neurons send the action back from the brain.
The lower animals function on a reflex system like the flatworm that have a net of connecting neurons surrounding their bodies. Higher life forms like crustaceans have a simple brain containing collections of neurons called a ganglia. Every ganglion controls a different part of the body. The brain of the higher animals evolved from the ganglia.
Humans can relate to the nervous system of animals because of the closely related structure that are shared between them and their animal counterparts. When a human is poked it is as annoying to an animal as it is to the human. When a human feels fear it is not much different from the fear an animal feels. Humans should realize that animals are more the same than different from them.