Formative Practice 12.4 (Form 4 Biology Textbook Exercise and Answer)

Question 1:
State the sequence of impulse transmission in the knee jerk reflex arc.


Question 2:
One example of reflex action is pulling the hand away from a hot object. Define the reflex action and state its importance.

Reflex action is defined as a quick and automatic response that does not involve thinking. Reflex action is important to protect ourselves from threatening situations and guarantees survival in the ever-changing environment.

Question 3:
Differentiate between voluntary and involuntary actions.

Voluntary action is an action under conscious control while involuntary action is an action we have no control over.

Question 4:
Someone who loses a leg due to a certain disease will still feel pain in the area where the limb was amputated. Explain why.

The condition may be due to the presence of sensory neurones at the amputated part. Therefore, the neurotransmitters secreted by the sensory neurones at the amputated part trigger nerve impulses and are interpreted by the brain as pain.

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