Voluntary actions involve conscious thought (thinking time).
Reflex actions do not involve conscious thought (thinking time) and happen very quickly to avoid unnecessary damage to the body.
One example of this is rapidly removing your hand from a hot plate before it gets burned.
A reflex action happens quickly because the reflex pathway is kept short and involves the smallest number of neurones and synapses possible.
A synapse is a small gap exists between two neurones, which an electrical impulse cannot pass across.
There are 2 synapses in the above reflex arc:
There are 3 neurones and 2 synapses involved in a reflex arc.
The association and motor neurones both begin with the cell body.