Pain sensation

Pain is induced by mechanical damage of tissue cells.
•As a result of damage bradykinin like peptides are released.
•These peptides lead to the stimulation of IV type afferent fibers in the region
Pain sensation is transmitted to the brain by anterolateral pathway.
•The type IV afferents synapse on the neuron in lamina I and IV region of spinal gray matter.
•These second order neuron are inhibited by somatosensoric large afferent fibers.

•That is why the pain sense can be decreased by mechanical stimuli applied from same dermatomal region of pain.

Spinal Cord

•The spinal cord is the part of the central nervous system that is surrounded and protected by vertebral column.
•In cross section, the spinal cord is organized as a butterfly shaped mass of gray matter surrounded by white matter.

•Gray matter of spinal cord are designated as name or romen numeral.
•The neuron cell bodies are organized into three discrete areas of the gray matter: the dorsal horn, the intermediate zone, and the ventral horn

•The CNS is made up not only of the brain, but also the spinal cord.
•The spinal cord is a thick, hollow tube of nerves that runs down the back, through the spine.

•The ventral horn contains the motor neuron bodies for the somatic motor system.
•The white matter contains many sensory tracts ascending to the brain and motor neuron axon descending from the brain