Nervous System(Human)

The nervous system is a rapid communication system .The main components are shown is fig
The control nervous system consists of :

• the brain ,situated inside the skull.
• the spinal cord,which extended from the base of the skull to the lumber region.

The spinal cord,protected from injury as it lies within the bones of the spinal column.The peripheral nervous system is a network of nerve fibres ,which are either:

or afferent nerves , which transmit signals from the body to the Brain or

Motor efferent nerves ,which transmits signals from the brain to the effector organs, such as muscles and glands.

The somatic senses are pain,touch, heat and cold. There sensation arise following stimulation of specialised sensory receptors at nerve ending found throughout the skin.

Nerve ending within the muscles and joints respond to change in the position and orientation of the body, maintaining posture and balance. Yet other sensory receptors are activated by stimuli in internal organs and control vital body functions

example: heart rate ,respiratory rate and blood pressure stimulation of any of these receptors sets up impulses that are conducted to the brain in sensory nerve .

communication along nerve fibers is by the electrical impulses that are generated when nerve endings are stimulated.nerve impulses can travel at a speed over the hundred metres per second, so responses response are almost immediate making a rapid and fine adjustments body function possible.

communication between nerve cell is also required since more than one nerve involved in the chain of event occurring between the initial stimulus and the reaction to it.

Nerve communicate with each other by releasing a chemical into tiny gaps between them. in only a few thousands of a second neurotransmitter quickly travel across the gap and either stimulates or inhibits the next nerve cell,thus ensuring the message is transmitted .

1.heart rate

2.blood pressure 

3.blood 
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