Practice question · Put in order
Order the events of a withdrawal reflex, from stimulus to the moment you feel it.
- An interneuron in the spinal cord relays it directly to a motor neuron.
- A pain receptor in the fingertip is stimulated by a hot surface.
- Only afterward does the signal reach the brain and conscious awareness.
- A motor (efferent) neuron drives the muscle to pull the hand back.
- A sensory (afferent) neuron carries the signal into the spinal cord.
Hints
- The hand moves BEFORE you consciously feel pain - so awareness is not step two.
- The whole arc runs in-and-out through the spinal cord; the brain is reached last.
Show the answer
- A pain receptor in the fingertip is stimulated by a hot surface.
- A sensory (afferent) neuron carries the signal into the spinal cord.
- An interneuron in the spinal cord relays it directly to a motor neuron.
- A motor (efferent) neuron drives the muscle to pull the hand back.
- Only afterward does the signal reach the brain and conscious awareness.
Why
The reflex completes entirely within the spinal cord - sensory in, interneuron across, motor out - and only afterward does the pain signal ascend to the brain. That is why you jerk your hand away before you feel the burn.
Practise Central Nervous System
The app has 6 more questions on this lesson, and keeps your place in the course. Psychology I is free to start.
More questions on Central Nervous System
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