Question

What is the rapid automatic response to a stimulus called?

Answer 1

Hint: All living organisms are fitted with a certain nervous system that is concerned with deciding the kind of responses to be reflected by the organism on encountering the stimulus. However, this response can be both voluntary or involuntary.

Complete answer
The rapid automatic response to any stimulus made by an organism is termed as Reflex
action. Reflex action is comparatively faster to the normal stimulus-response process of the
Central Nervous System (that is, Brain + Spinal cord) as it does not involve the brain. It
comes in action only in intense dangerous situations where the spinal cord comes in charge
and suggests anyhow escape from the situation.
Nervous system like all other systems of a living body is well coordinated and managed by
various organs. It helps the organism to respond to the environment, maintain touch with
reality and that eventually helps in maintaining individuality of the organism. This system is
capable enough to complete the entire process within a fraction of a second. Involvement
of the brain as a decision maker is common to the majority of instances but sometimes it
happens that the stimulus is so intense that even a fraction of a second becomes enough to
negate the situation. Therefore, our reflex system, in order to prevent the organism from
any subsequent harm successfully manages to respond to the imposed environment
voluntarily, in the best possible manner. This process helps the organism to escape from
dangers.

Note:
The general pattern of response made by the system involves receival and transfer of impulse from environment to the CNS, followed by decision making by the brain and eventual response to the situation. Whereas activity of the brain is skipped in case of reflex action due to the formation of reflex arc..