the Pacinian corpuscle

Pacinian Corpuscles detect pressure and they are in the deep layers of the skin - fingertips and soles of the feet have high numbers - and in joints

the Pacinian corpuscle produces a nervous impulse in response to pressure = a generator potential → converts mechanical energy

so it is acting as a transducer

• pressure causes the shape of the pacinian corpuscle to change, the shape change causes the membrane of the neurone to stretch

• this causes the stretch-mediated sodium channels to widen

• now sodium ions diffuse through the channels into the neurone → causing the interior of the neurone to become positively charged - the neurone has depolarised

the generator potential causes a wave of depolarisation to pass down the sensory neurone to the central nervous system - this wave of depolarisation is called an action potential