The Pacinian Corpuscle (touch).

• The Pacinian Corpuscle is a receptor found in the skin, which responds to mechanical pressure.
• Pacinian corpuscles are transducers i.e. they convert one form of energy into another.

  Mechanical Energy -> Electrical Energy.
• The electrical energy generated is known as the generator potential.
• A Pacinian Corpuscle is the start of a sensory neurone, wrapped around layers of tissue called lamellae.
• In a normal resting state, sodium ions are moved out of the cell by active transport.
• Stretch mediated sodium ion channels in the plasma membrane of the sensory neurone in the centre of the receptor are too marrow to allow sodium ions to re-entre the neurone.
• When pressure is applied the membrane around the neurone becomes deformed. The sodium ion channels are opened and are now wide enough so sodium ions diffuse into the neurone.

  The influx of sodium ions changes the potential of the membrane.

  If the generator potential exceeds the threshold, voltage gated sodium ion channels open causng an action potential that passes along the neurone towards the CNS.