SPINAL CORD – FIRST PROCESSING LEVEL FOR THE PAIN STIMULI
The cord conveys the 31 spinal nerve pairs of the peripheral nervous system as well as central nervous system pathways that innervate skeletal muscles. Inside the spinal cord, there is grey matter surrounded by white matter. The dorsal horn is the dorsal section of the grey substance of the spinal cord.
Sensory nerve fibres coming from the periphery end here and neural impulses are switched to the second sensory neuron at excitatory synapses ascending to higher centres of the brain (afferent/ascending pathways).
In the other direction, motoneural responses and pain modulating inhibitory signals coming from the higher levels of the CNS descend the spinal cord via the efferent/descending pathways.