The basic nervous system function includes—receiving sensory information (input), processing of the input and production of motor responses. The nervous system is formed of two parts that are integrally linked with each other. The brain and the nervous system have multiple functions that are extremely important for normal functioning of the body. The sensory information originating from stimulation of receptors by changes in the external and internal environment are carried to CNS through afferent nerves fibers. In the CNS, this information is processed through complex neuronal (synaptic) pathways.
As a result of above, commands are discharged through efferent nerve fibers to effectors organs (that is, muscles and glands) for production of motor responses or change in activity of the effectors organs. The central processing also causes stimulation of feelings (sensations) and storage of information as memory. The stored memory as the nervous system function in turn helps in dispensation of future input for other mental functions like emotion, power of thinking and judgment, intelligence, personality etc.
From our above discussion, it is apparent that the following nervous system functions are performing:—
Conscious sensation as a nervous system function
Nervous system is responsible for stimulation of conscious sensations by which we can feel the changes occurring within the body or around us. A conscious sensation such as, sight, hearing, smell, taste and feeling of touch, temperature, pressure, pain etc. are aroused when the afferent nerve impulses reach the highest centre of central nervous system or cerebral cortex of brain.
Mental functions as the nervous system function
Nervous system is responsible for higher mental functions like memory, intelligence, power of thinking, judgment, emotion, personality etc. These functions are specially developed in higher animals as well as humans having a highly developed brain.
Control of voluntary movements is the nervous system function
When a skeletal muscle is moved as contraction or relaxation according to our desire or will power, it is called voluntary movement. Such movements are governed by conscious sensation and initiated by cerebral cortex, and they help in locomotion, speech etc. is another nervous system function.
Control of reflex actions is a nervous system function
When a sensory input elicits a motor response without or prior to stimulation of conscious sensation, it is called reflex action. Nervous system regulates the activity of all the three types of muscles, those are skeletal, smooth and cardiac muscles and glands through various reflexes. Reflex control of skeletal muscles helps to uphold body posture, breathing etc., whereas reflex responses of other muscles and glands maintain co-ordination between the activities of different systems so that the whole body may function as an incorporated unit.
Some parts of the nervous system i.e., brain secrete hormones called the ‘neuro-hormones’ is also another nervous system function.