Transduction

When exposed to painful or noxious stimuli specialised nerves cells, or neurones, called nociceptors are stimulated. These neurones are particularly tuned to respond to mechanical, thermal or chemical stimuli that are strong enough to cause or indicate tissue damage.

Nociceptors are located widely in skin, muscle, bones and viscera. They are classified according to:

• The type of stimulus they respond to – many respond to more than one and are called polymodal.
• Their temporal characteristics – the speed at which they respond.
  and
• Their conduction velocity of the axons that carry signals from the receptive nerve endings