QS Study

The nervous system is the most important organization which correlates the adjustments and reactions of an organ to internal and external environmental condition. It is a complex network of nerves and cells that hold messages to and from the brain and spinal cord to different parts of the body. The nervous system takes in information through our senses, processes the information, and triggers reactions, such as making your muscles move or causing you to feel pain.

The basic design of Nervous System:

Neuron – The basic Functional Unit of CNS

The CNS contains more than 100 billion neurons; these neurons are arranged into a multitude of differently organized neural networks that determine the functions of the nervous system.

Fig: Basic organization of the nervous system

Sensory receptors – a Sensory division of the nervous system

The sensory receptors and sensory neurons constitute the afferent pathway of the nervous system. Which convey information from cutaneous and special sense receptors. This sensory information is correlated within the nervous system and can cause an immediate reaction from the brain, or memory of the experience can be stored in the brain for minutes, weeks, or years and determine bodily reactions at some future date.

Motor division – The effectors

The motor neurons and effectors constitute the efferent pathway or motor division. The muscles and glands are called effectors because motor neuron performs following functions –

(i) Contraction of appropriate skeletal muscles throughout the body.

(ii) Contraction of smooth muscle in the internal organ.

(iii) Glandular secretion.

Processing of Information “Integrative” function of nervous system.

The nervous system of higher species has the ability to store sensory information received during past experiences and this information when appropriate is integrated with other nervous impulses and channeled into the common efferent pathway.