Touch receptors in the skin provide us with tactile information about qualities like the
position, shape, texture, pressure, and movement of things we come in contact with.
They are often classified as either rapidly-adapting or slowly-adapting.
Rapidly-adapting receptors are activated when a stimulus is first encountered, but fall
silent if the stimulus remains present.
They are important for detecting things like movement.
Slowly-adapting receptors keep responding to a continuously present stimulus and are
important for detecting things like the size and shape of objects.
Touch receptors also vary in the size of their receptive field, or the area they can detect
Having many smaller receptive fields typically allows for better tactile discrimination than
fewer, large receptive fields.
There are four main types of touch receptors found in hairless skin (like that of the hand).
Merkel’s discs are slowly-adapting receptors that have very small receptive fields and
high spatial resolution.
They are especially dense in the fingertips, and are best-suited for processing information
about shape and texture.
Meissner’s corpuscles are rapidly-adapting receptors.
They have relatively small receptive fields, but their spatial resolution is inferior to
that of Merkel’s discs.
They are especially effective at transmitting information about movement between the skin
and another surface.
This can be used to sense texture and to detect if an object is sliding past the skin--which
is important for maintaining grip.
Pacinian corpuscles are rapidly-adapting receptors with very large receptive fields.
They are thought to be most effective at transmitting information about vibrations objects cause
when they are contacted or grasped by the hand.
This information may be important for the use of tools.
Ruffini’s endings are slowly-adapting receptors with large receptive fields.They are poorly
understood, but seem to respond most to skin stretching, like what would occur with the movement
of the fingers.
This information might be especially important in generating awareness of finger and hand