Nervous impulses

A communicator

The human nervous system is the body’s regulation and communication centre. It can be divided into two parts: the central nervous system which comprises the encephalon (brain, diencephalon, cerebellum and brain stem) and the spinal cord, and the peripheral nervous system formed by the nerves attached to the central nervous system.

The nervous system receives information about changes in the body and then decides to act on this information if necessary. One part of the nervous system is called voluntary, as it concerns nervous impulses transmitted to the muscles which we can control consciously. The other part is named involuntary as it concerns the nervous impulses on which we have no influence, like the heartbeat or digestion for example. Nervous impulses thus ensure message transmission within the body.

An electric signal

The nervous impulse is also called ‘action potential’. It refers to the electric signal produced by a neuron when stimulated. This signal is then transmitted by synapses, or connections between the cells. There are two types of nervous impulses. The first pass from the skin’s receptors or from internal organs to the brain and relay information from the brain to the muscles and glands. The others transmit information between two types of neurons.

Fast communication

While an electric current circulates at a speed of around 300 000 km per second, nervous impulses in the human body are much slower: 100 m per second. This speed is still more than enough to transmit information extremely quickly through the body.