Different parts of the body vary in their sensitivity to tactile and painful stimuli. These varying responses are based largely on the number and distribution of receptors. For example, the cornea is several hundred times more sensitive to painful stimuli than are the soles of the feet.

Are pain receptors evenly distributed?

Pain receptors, also called nociceptors, are a group of sensory neurons with specialized nerve endings widely distributed in the skin, deep tissues (including the muscles and joints), and most of visceral organs.

What are the three types of pain receptors?

Within the central nervous system, there are three types of opioid receptors which regulate the neurotransmission of pain signals. These receptors are called mu, delta, and kappa opioid receptors.