Reflex action is an immediate and involuntary response given to a stimulus from the environment.
The reflex action is so spontaneous that it does not require thinking or control by our brain.
Reflex actions are not controlled by brain. But the control and coordination is maintained by the reflex actions by which the load on the brain is reduced. They are of survival value as a person is saved from a dangerous situations due to reflex actions.
The path of reflex action is as follows : This is also known as reflex arc. Sense organs->Sensory neurons->Towards the spinal cord -> Coordination neuron -> Motor neuron -> Muscle or gland.