Question

Which of the following is not a reflex action?
A) Salivation
B) Sweating
C) Withdrawal of hand when pinched by the needle
D) None of these

Answer 1

A reflex action is an involuntary and sudden response to a stimulus. This action takes place so as to minimise any damage to the body from a potentially dangerous condition. Example withdrawal of hands-on touching hot surfaces. Coughing and sneezing is also an example of reflex action.

Complete answer:
Reflex action is the action that does not require any thought input. These are the sudden response by the body which helps the body to prevent any dangerous damage. Some examples of reflex action are knee jerk, closing of eyes in extremely bright light. These actions are very fast and are carried out without thinking.

Let us discuss the options given-
A) Salivation-The secretion of saliva is controlled by the reflex arch. The saliva is secreted by the salivary gland in response to taste, swallow and masticate food(stimulus).
B) Sweating- Sweating is also known as perspiration. It is secreted by the sweat glands. Sweating is the mechanism of maintaining body temperature. Sweating is regulated by the hypothalamus of the brain.
C) Withdrawal of hand when pinched by needle- This is a reflex action that is controlled by reflex arch. In this needle is the stimulus against which the hand withdrawal takes place as a very sudden and fast response.

Therefore the correct answer is option ‘B’.

Note: The reflex arc is maintained by the neurons sensory, effector and motor neurons. It is an unconscious response against the danger that prevents us from pain. The reflex arc is controlled by the brain and the spinal cord.