Question

Which of the following is not an involuntary action?
A. Vomiting
B. Salivation
C. Heartbeat
D. Chewing

Answer 1

Involuntary actions are not under our conscious control. They are controlled by the autonomic nervous system.

Complete Answer:
- The nervous system is a part of the body that regulates its voluntary and involuntary activity and transmits signals to various areas of the body. The nervous system consists of two main parts, the central nervous system (CNS) and the peripheral nervous system (PNS). The brain and the spinal cord make up the CNS. The brain is the body's control centre. It governs thought, memory, voice, and action, and regulates the role of several organs.
- Actions in our body can be categorised as either voluntary or involuntary. Voluntary actions are those that are under our control and involve conscious thinking. Involuntary actions are those actions that are not under our authority and that happen spontaneously.
- The autonomic nervous system (ANS) is part of the peripheral nervous system that regulates the visceral activity of the human body , e.g. blood pressure, urinary bladder activity, body temperature regulation, etc. Vomiting, salivation and heartbeat are involuntary actions under the influence of the autonomic nervous system. These actions are not under the control of one's will.
- Chewing is a voluntary action. It can be controlled by our conscious will. The food is chewed voluntarily with teeth that are regulated by the mastication muscles.

Thus, the correct answer is option d i.e., Chewing.

Note: Involuntary actions are under the control of the autonomic nervous system. The autonomic nervous system controls the basic visceral processes essential for the maintenance of natural body processes.