The Components of a Reflex Arc

A reflex arc is a simple, automatic response to stimuli to protect the body from potential harm. It does not involve the conscious part of the brain.
The main components of a reflex arc are the receptor, sensory neuron, coordination centre (the spinal cord or brain), motor neuron, and effector.
The receptor detects the stimulus. This could be any part of the body sensitive to changes in the environment, such as the skin detecting a change in temperature.
Once the stimulus has been detected, a signal is sent along a sensory neuron to the coordination centre. This signal is called an impulse.
Sensory neurons are connected to motor neurons in the coordination centre (spinal cord or brain) through synapses. These neurons communicate via an electrical signal and the release of neurotransmitters across the synapse.
The coordination centre processes the signal and then sends an impulse along a motor neuron.
The motor neuron transports the impulse to the effector, which is usually a muscle or gland. The effector then responds to the impulse.
An example of this is the withdrawal reflex, which happens when you accidentally touch a hot object. The reflex arc causes the muscles in your hand to contract, pulling your hand away from the hot object.
The entire process of the reflex arc happens very quickly to minimise any potential damage to the body.
Understanding this process is essential as it shows the role of different types of neurons and the function of the nervous system in protecting the body from harm.