What do pacinian corpuscles detect?

Answer 1

They are mechanoreceptors that detect pressure, and are found in the skin and also in joints and tendons. Naked nerve endings lie in the centre of the corpuscle surrounded by concentric layers of connective tissue separated by viscous gel (looks a little bit like an onion!).

Mechanical stimuli are converted into electrical impulses as follows:

• Transduction occurs - the production of a small receptor potential of about 1mV across the receptor membrane when pressure is applied.
• The receptor potential is produced by deformation of the receptor membrane, which interferes with ion channels embedded in the membrane and causes leaks, allowing an influx of sodium ions.
• A generator potential is produced and an impulse is generated at the first node of ranvier. Electrical impulses are transmitted along the neurone.

The presence of gel-filled lamellae in the Pacinian corpuscles provides a mechanical filter of the stimulus. If pressure is applied rapidly the membrane of the corpuscle is deformed for a few milliseconds until the gel flows and the membrane resumes its normal shape. If pressure is applied slowly the gel flows away from the stimulus so the membrane is not deformed, and no receptor potential is generated. The greater the pressure applied to the corpuscle, the greater the receptor potential. Once the pressure reaches a critical size (te threshold) an action potential is triggered.

Answer 2

Pacinian corpuscles are receptors that respond to a specific stimuli of mechanical pressure. They have stretch-mediated sodium channels, mechanical pressure will distort and stretch these channels, causing them to open and hence an influx of sodium ions will enter the axon. This causes depolarisation and hence a generator potential is produced. The pacinian corpuscle acts as a transducer, transducing the energy of the stimulus into electrical impulses in which the brain can understand.

Answer 3

Pressure