Question

Differentiate between voluntary action and reflex action.

Answer 1

Hint: Voluntary actions are conscious responses while reflex actions are involuntary responses to the stimulus.

Complete Answer:
We are blessed with an intricate and complex nervous system that controls and coordinates various body responses to different stimuli perceived by the body. The nervous system not only tells you what you are seeing, hearing, tasting, smelling and touching, but also controls the movement of your digestive system, heart beats, etc. that you do not even feel.
Infact, sometimes you take sudden actions like withdrawing your hand when accidentally touching an extremely hot surface is also an unconscious response that your nervous system is controlling.
The peripheral nervous system is made up of different sensory and motor neurons, that take the stimulus to the central nervous system (brain and spinal cord) and bring the response from them respectively.
Now, the actions or responses that you perform knowingly, like reading, walking, singing are called the voluntary responses. You can control their happening. The actions you perform in a sudden manner like shivering in cold, withdrawing your hand from an hot object, that you do without giving a second thought are called reflex actions.

Let us mark the differences between these two types of actions:

Voluntary Actions	Reflex Actions
These are initiated in the cerebrum after receiving a thoughtful stimulus.	These are initiated by a sudden stimulus and are processed by the spinal cord. From the spinal cord these are transmitted to the brain.
The responses originate in the brain and are transported to the effector organs via spinal cord.	The responses originate in the spinal cord.
A complex system of sensory neurons, relay neurons and motor neurons is involved.	A reflex arc made up of sensory organ, sensory neuron, motor neuron and effector organ is involved.
Multiple synapses are involved.	Only two synapses are involved.
Stimulus passses to the opposite side, the left side of the brain controls the right side of the body and vice versa.	Stimulus, neurons, action all on the same side of the body.

A reflex arc is shown below:

Note: The reflex actions and involuntary actions are controlled by the autonomic nervous system that manifests the unconscious responses like sneezing, peristalsis, etc. The voluntary actions are controlled by the somatic nervous system.