Difference between Reflex action and Involuntary action
A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus.
An involuntary action is one which occurs without the conscious choice of an organism. If it occurs specifically in response to a stimulus, it will be known as a reflex.
All reflex actions are involuntary in nature but all involuntary actions are not reflexes as the beating of heart is an involuntary action but is not reflex action.
A reflex action may involve any muscle or a gland as we withdraw our hand on touching a hot object BUT all involuntary actions involve only smooth i.e., involuntary or cardiac muscles.
Reflex actions are at the level of spinal cord whereas the involuntary actions generally involve brain too.