The following are all examples of a simple reflex action, except

Analyze the question: We need the one option that is NOT a simple reflex action.

Concept: A simple reflex action is an automatic, rapid, involuntary response to a stimulus. It does not need conscious thought. The pathway is:

Stimulus → Receptor → Sensory neuron → Spinal cord (or brain stem) → Motor neuron → Effector → Response

Check each option:

• A. Swallowing: Once food reaches the back of the throat, swallowing happens automatically. It is a reflex.
• B. Sneezing: An irritant in the nose triggers an involuntary response. It is a reflex.
• C. Walking: You decide to walk, and it needs coordination of many muscles and the brain, especially the cerebrum and cerebellum. It is a voluntary action, even though it can become habitual with practice. It is not a simple reflex.
• D. Blinking: The eye closes automatically when something approaches or touches it. It is a reflex.

Answer: Walking is voluntary and controlled by conscious thought, so it is the exception.

Exam tip: Ask yourself, "Do I have to think about it or decide to do it?" If yes, it is voluntary. Sneezing, blinking, coughing, knee-jerk, withdrawing your hand from a hot object and pupil constriction are classic reflexes. Walking, talking, writing and running are voluntary.