Imagine that you have gone to the garden to pick a rose. Unfortunately, when reaching for a flower, your thumb encounters a thorn and you jerk your hand away. What is the order in which information is communicated, from the time of the prick through withdrawal of your hand and realization of pain?

Question

Quizplus · Accepted Answer

The correct sequence starts with the sensory neuron detecting the pain from the thorn prick, then the signal is relayed to an interneuron (usually in the spinal cord or brain), which processes the information and sends a signal through a motor neuron to withdraw the hand. The brain is involved in the perception of pain, which might occur simultaneously or slightly after the reflex action to withdraw the hand.  Sensory neurons take the information from the environment (the thorn) to an interneuron in the spinal cord. This interneuron stimulates a motor neuron, which excites appropriate muscles to pull your hand away from the thorn. Only after this has occurred does the brain receive the information; the perception of pain occurs in the brain after you have physically responded to the danger.

Imagine That You Have Gone to the Garden to Pick