Describe the impulse process in a simple reflex action

1. Sensory neurone detects a stimuli via sensory receptors e.g. a hot pan

2. This sends an impulse up the sensory neuron to the brain or spinal column (together known as the central nervous system or CNS)

3. Here te impulse crosses over a synapse to a relay neurone via release of chemicals

4. This relay neuron carries it to a motor neuron, where it crosses another synapse

5. The impulse then runs down the motor neuron to a muscle (effector) which activates it causing movement e.g. dropping the hot pan

Note - the effector may also be a gland, causing hormone release, Also draw a synapse