structure and function of sensory, relay and motor neurons

• sensory neuron- detect sensations at sensory receptors, action potential travels across nerve passing along the myelinated axon then the electrical signal is converted into a chemical signal to cross the synapse.
• Relay neurone, function- after synaptic transmission a new action potential forms in the dendrites, this neuron is in the spine, and sends a signal to the CNS but also immediately sends a signal along its axon to the motor neuron
• motor neuron- detects signal from the relay neuron via synaptic transmission and passes this signal along its own myelinated axon to stimulate an effector (eg muscle group in the arm moving it away from the source of pain)
• on axons you have myelin sheath