Why Are Some Neurons More Than a Meter in Length?

Neurons are the cells that comprise your nervous system. They carry information throughout your brain and into various parts of your body through the use of electrical signals. In large vertebrates, neurons may need to be several feet long.

Why Some Neurons Can Be Over a Meter in Length

• Some neurons are over a meter in length because they need to transmit signals from the brain to various extremities. Neurons that achieve this length are often located in the spinal cord and in the extremities.

The Axon

• In long neurons, it is the axon that achieves the majority of the length. The axon's purpose is to send information from the cell body to the next cell, or in some cases the tissue it affects (muscle, for instance).

Motor Neurons

• Neurons of this length are motor neurons, meaning that they exist outside the brain to transmit signals from the brain to to body. Their axons often have a substance called myelin, which forms a sheath around the axon so that it may transmit electrical impulses faster, allowing messages to and from the brain to happen in a timely manner. Because many motor neurons can reach a length of several feet, this is important. Without myelin, we would not be able to respond in time to a dangerous stimulus.