Human Nervous System or Human Brain
Brain is the main coordinating centre of the body. It has three major parts :
(a) Fore-brain (b) Mid-brain (c) Hind-brain
(a) Fore-brain ;: It is the most complex or specialized part of the brain. It
consists of cerebrum.
(i) Thinking part of the brain.
(ii) Control the voluntary actions.
(iii)Store information (Memory).
(iv)Receives sensory impulses from various parts of the body and integrate
(v) Centre associated with hunger.
(b) Mid-brain : Controls involuntary actions such as :
- Change in pupil size.
- Reflex movements of head, neck and trunk.
(c) Hind-brain : It has three parts :
(i) Cerebellum : Controls posture and balance. Precision of voluntary
actions e.g., picking pen.
(ii) Medulla : Controls involuntary actions e.g., blood pressure, salivation,
(iii) Pons : Involuntary actions, regulation of respiration.
Protection of Brain and Spinal Cord
(a) Brain : Brain is protected by a fluid filled balloon which acts as shock
absorber and is enclosed in cranium (skull or brain box).
Control And Coordination
(b) Spinal Cord : Spinal cord is enclosed in vertebral column.
Limitations of Electric communication/Nervous system :
(a) Electric impulse will reach only to those cells that are connected by
(b) After generation and transmission of an electrical impulse, the cell
takes some time to reset its mechanism before transmitting another
impulse. So cells cannot continually create and transmit impulse.
(c) Plants do not have any nervous system.