Nervous System

The nervous system is very important in helping to maintain the homeostasis (constant environment) of the human body.
A series of sensory receptors work with the nervous system to provide information about changes in both the internal and external environments.
The human nervous system is a complex of interconnected systems in which larger systems are comprised of smaller subsystems each of which have specific structures with specific functions.

Structure

Neurons (nerve cells) are the basic elements of the nervous system, consisting of a cell body, dendrites and axon.

Terminal end fibres are located at the ends of the axon. At this point, the electrical impulse that travels down the neuron causes chemicals called neurotransmitters to be release into a gap called the synapse.

These neurotransmitters cause a new electrical impulse in the next neuron in the chain.

Components

All bodily activities, voluntary and involuntary, are controlled by the nervous system.

There are two major components:

(1) Central nervous system (CNS)

Made up of the brain and spinal cord
These organs work together to integrate and coordinate sensory and motor (e.g. movement) information for the purpose of controlling the various tissues, organs and organ systems of the body.
The CNS is responsible for higher neural functions, such as memory, learning and emotion.

(2) Peripheral Nervous system (PNS)

Made up of all the nerves that lead into and out of the CNS.
Collection of peripheral nerves, ganglia and specialised sensory structures that, as a system, carries sensory and motor information between the CNS and other organs and tissues of the body.
2 divisions – sensory (or afferent) division and motor (or efferent) division.