The Pain System in Oesophageal Disorders: Mechanisms, Clinical Characteristics, and Treatment

Figure 1

The anatomy and physiology of the pain stimulus. Pain is sensed in a nociceptor in the tissue, which generates an action potential along the nerve fibre of the first-order neuron. The action potential travels proximally towards the other end of the neuron and is transmitted to the second-order neuron in the spinal cord through a synapse mediated by neurotransmitters. The second-order neuron then generates an action potential that travels further proximally through distinct nerve bundles (fasciculi) in the spinal cord and synapses to the third-order neuron in the brain.