Answer:
A pain receptor detects the shard a glass (the stimuli) and triggers an electrical impulse along the sensory neurone. The electrical impulse reaches a synapse and neurotransmitters diffuse across the gap, triggering an electrical impulse along a relay neurone in the spinal cord. The electrical impulse reaches a synapse and neurotransmitters diffuse across the gap, triggering an electrical impulse along a motor neurone to the leg muscles (the effector). This causes the muscles to contact and lift your foot
