The major functions of the nervous system in humans are as follows:
- It keeps us informed about the outside world through the sense organs.
- It enables us to remember, think and to reason out.
- It controls all voluntary muscular activities like running, speaking, etc.
- It regulates several involuntary activities such as breathing, beating of the heart, movement of food through the food canal, etc.
Thus, the nervous system makes body parts work together in proper coordination, as one single integrated unit.
Some Basic Terms
Stimulus: An agent or a sudden change of the external or the internal environment that results in a change in the activities of the organism.
Impulse: A wave of electrical disturbance that travels across the nerve cell and its fibre.
Response: A change in the activity of the organism caused due to stimulus.
Receptors: The nerve cells which on receiving the stimulus, set up wave of impulses towards the central nervous system (brain and spinal cord).
Effectors: Muscles or glands, which on receiving the impulse from the brain or spinal cord contract or secrete substances.
Nerve: A bundle of axons (nerve fibres) of separate neurons connecting the central nervous system with other parts of the body.
Sensory (afferent) nerve or the cell: Bringing the impulse from the receptor (sensory organ) to the main nervous system.
Motor (efferent) nerve or the cell: Carrying the impulse from the main nervous system towards a muscle or a gland.