The diagram given below is an external view of the human brain. Study the same and answer the questions that follow: The diagram given below is an external view of the human brain. Study the same and answer the questions that follow:
State the main functions of the parts labelled A and B.
Topic: Functions of cerebrum and cerebellum
Answer
CEREBRUM (A): the seat of INTELLIGENCE, CONSCIOUSNESS, MEMORY, REASONING and WILL POWER. It controls and initiates all VOLUNTARY activities and interprets the sensations received from the sense organs.
CEREBELLUM (B): it COORDINATES muscular activity, making movements smooth and precise, and MAINTAINS the BALANCE and posture of the body.
THE DISTINCTION between the two is what the examiner is testing by asking about both together: the CEREBRUM DECIDES to make a movement, the CEREBELLUM CONTROLS how it is carried out.
A person with cerebellar damage still INTENDS to pick up a cup and still tries, but the movement is jerky, misjudged and unsteady. The intention is intact; the execution is not.
That is also why ALCOHOL, which depresses the cerebellum, causes staggering and loss of balance rather than loss of intention.
The third part completes the set: MEDULLA OBLONGATA — involuntary activity such as heartbeat, breathing and peristalsis.