DEFINITION – What does Nerve mean?
A nerve is like a smart electrical control cable; it is a long set of neuron fibres (called axons) that are all twisted together, and that connect the peripheral nervous system with the body in both directions, all at once providing driving control to every organ and muscle while gathering intelligence via sensory receptors. Essentially, nerves are very specialized cell strands in our bodies that function like a messenger network, delivering miniscule electrical signals all across the body and back to the origin.
Referred to in scientific circles as neurons, or nerve impulses, they are the basis of the nervous system, and are the elements that drive your mechanical reflexes. Each individual axon fibre is wrapped in a layer of tissue called the endoneurium which ensures its electrical signal doesn’t stray. Just like a cable, each wrapped fibre is then twisted together with many other fibres, becoming what is referred to as a fascicle, and then each fascicle is wrapped in another layer of tissue, called the perineurium. Finally, sets of fascicles are wrapped in a layer of epineurium. Within the CNS (the central nervous system) these triple-wrapped axon strands are collectively known as tracts and are what connect the different hemispheres of the brain with the brainstem and the spinal cord.
BREAKING DOWN – Nerve
When you inadvertently walk close to a fire, your sensory receptors detect the sound of flames, the smell of smoke, and the feeling of heat, and instantly transmit those signals to the brain for processing. In response, the brain instantly transmits signals via the nerve network to an effector, in this case the muscles of the legs, commanding them to “run!”.
Nerves are classified into two distinct groups based on their purpose and function:
- Afferent Fibre: This connects sensory neurons to the CNS for processing.
- Efferent Fibre: After processing, motor neurons in the CNS conduct impulses to the muscles across these fibres.
A nerve fibre works by channeling electro chemical impulses (information packets) from one part of the body to another. Each impulse, or signal, travels extremely fast – as much as 120 meters per second. Transference of information across neurons occurs via a synapse which converts the electrical signal to a chemical signature and then back again.