What is a reflex arc? Explain how it works, using an example, and draw it with all its parts labelled.
How to lay out the answer. Follow the frame, then write it in your own words.
1 · Define in one line. A reflex arc is the pathway of a reflex action: a sudden, automatic response to a stimulus, controlled by the spinal cord without the involvement of the brain.
2 · Give the path. Stimulus → receptor → sensory neuron → spinal cord (association neuron) → motor neuron → effector.
3 · Use an example. Touching a hot pan: heat receptors in the skin start the impulse, and the arm muscle pulls the hand away.
4 · Explain why it is fast. The response is made in the spinal cord; the brain is told afterwards, so the pain is felt a moment later.
5 · Name the two kinds. Natural (inborn), such as blinking; conditioned (acquired), such as the mouth watering at a familiar smell.
6 · Draw the reflex arc. [Diagram: receptor in the skin, sensory neuron, spinal cord with gray and white matter, association neuron, motor neuron, effector muscle, arrows]
7 · Link to daily life. Pulling your hand back from a hot tawa protects you before you even think.
8 · Close in one line. So reflexes guard the body against sudden harm.
Scoring tip: Name all the parts in order and draw arrows; the label spinal cord is a must.
