Science (086) — AI-generated practice question

When we touch a hot object, the sensory receptors detect the stimulus and the nerve impulse travels to the spinal cord, where a reflex arc is formed. The spinal cord immediately sends a motor signal back to the hand muscles, causing withdrawal — all without involving the brain. This is why the hand pulls back almost instantly.

However, the sensation of pain is felt only after the same impulse travels further up to the brain (fore-brain), where it is consciously interpreted. This takes slightly longer, causing the time delay.

This reveals that in a reflex action, information is processed at the spinal cord level, not the brain, making the response faster and protecting the body from injury before conscious thinking occurs.

Source: Chapter 6, Section 6.1.1 – Reflex Actions

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• Examiners look for: (1) reflex arc at spinal cord level = fast withdrawal, (2) pain felt when impulse reaches brain = slight delay, (3) the significance — reflex bypasses brain for speed.
• Key term to use: reflex arc, spinal cord, fore-brain.
• Common mistake: saying the brain controls the reflex — it does NOT; the spinal cord does. The brain only receives the information after the response has already happened.
• The passage explicitly states: "Reflex arcs are formed in this spinal cord itself, although the information input also goes on to reach the brain."