Question

Which of the following is not an organ of the central nervous system?
A. Brain
B. Spinal cord
C. Medulla oblongata
D. Vagus

Answer 1

Hint: Central Nervous System (CNS) includes two parts: the brain and spinal cord and it mainly controls the functions of both body and mind. The brain plays a key role in the control of most of the functions like sensations, thoughts, etc. while spinal cord carriers signal pathways.

Complete answer:
The major function of the central nervous system is integration and coordination. The central nervous system controls directly or indirectly every internal organ system whether it is digestion, respiration, excretion, reproduction, etc.
A. Brain- The brain is the part of the central nervous system. The cerebrum which is the largest part of the brain plays the main role in the control of voluntary actions such as speech, communication, memory, awareness, etc. The brain plays every important role in the body system.
B. Spinal cord- Spinal cord is another segment of the central nervous system. Some of the reflex movements occur through the spinal cord pathways without the interruption of brain structures. The spinal cord carries messages between the brain and peripheral nerves. It plays a vital role in the communication between the brain and the body.
C. Medulla oblongata- It is the part of the brainstem (posterior part of the brain adjacent or structurally continuous with the spinal cord ) which is a long stem-like structure making this part of the brainstem. It is responsible for involuntary actions i.e. sneezing or vomiting also by regulating several basic functions including swallowing, vasodilation, etc.
D. Vagus- Vagus is the X cranial nerve also called a pneumogastric nerve. It expands its origin in the brainstem via the neck and thorax to the abdomen. The Vagus nerve is the major segment of the parasympathetic nervous system having vital body functions including the control of the immune response, digestion, heart rate, etc.

Hence, the correct answer is option (D).

Note: Central nervous system working in order with the peripheral nervous system and permit the body to control and react to the stimulus. It controls our body voluntarily as well as involuntary actions. It refers to as central as it combines information from the whole body and then coordinates functions all across the whole organism.