Pacinian Corpuscle (A-level Biology)

Pacinian Corpuscle

Detecting Pressure

Pressure Receptors in Skin

• The Pacinian corpuscle is a type of touch receptor that responds to pressure.

• These receptors are also called mechanoreceptors, meaning that they detect pressure and vibrations. They are found in the skin, fingers and toes.

• The corpuscle is comprised of many layers of lamellae, a type of connective tissue. The tissue is wrapped around the end of a sensory neurone.

Stimulation of a Pressure Receptor

The following steps lead to an action potential:

1. The corpuscle is compressed by the stimulus. When pressure is applied, the lamellae become deformed, changing the shape of the corpuscle.
2. Stretch-mediated Na+ ion channels open. The membrane of the sensory nerve cell stretches, causing ion channels to open.
3. Na+ ions move into the sensory neurone. This causes a generator potential, which can cause an action potential.

The Pacinian corpuscle will only respond to mechanical stimuli – it is specific.