What is the role of a motor neurone?

A motor neurone is responsible for carrying signals from the brain, to muscle tissues, glands and organs that then carry out a specific outcome (e.g. physical movement).

A motor neuron, as its name suggests is a nerve cell which effect movement by transmitting indirect signals from the brain ( via the spinal cord) to effectors of muscle cells/fibers. Memory aid: motors move!

In the central nervous system, there are three main neurons; relay, sensory, and motor. All of them work together to perform a REFLEX ACTION.

Have you ever touched a really hot cup of tea and then suddenly yanked your hand away because you realized it was hot? You do that without thinking - it’s a reflex.

There are steps to how the body does this as well. Motor neurons are a part of the process. To understand how they play a role, we need to understand the whole process.

Let’s take the example of the hot cup of tea- here are the steps that a reflex arc would contain.

1. Receptor in the skin detects a stimulus (the change in temperature)
2. Sensory neuron sends electrical impulses to a relay neuron, which is located in the spinal cord of the nervous system. Relay neurons connect sensory neurons to motor neurons.
3. Motor neuron sends electrical impulses to an effector (the muscle taking action).
4. Effector produces a response (muscle contracts to move hand away).

So the motor neurons send the final message to the effector (the muscle or body part that moves to get away from the high temperature.

Motor neurone transmits the electrical signal from the spinal cord to the effector (a muscle which carries out the response)