Touch Receptors in Hairless Skin

General Properties of Touch Receptors

• Provide tactile information regarding position, shape, texture, pressure, and movement.

• Classified into two response types:

  • Rapidly-adapting: Activate upon initial contact with a stimulus and fall silent if the stimulus remains present; detect movement.

  • Slowly-adapting: Continuously respond to a present stimulus; detect size and shape.

• Vary in receptive field size (the area where signals are detected):

  • A higher density of smaller receptive fields provides better tactile discrimination than fewer, larger fields.

Four Main Touch Receptors in Hairless Skin

• Merkel's discs:

  • Slowly-adapting receptors with very small receptive fields and high spatial resolution.

  • Especially dense in fingertips; optimal for processing shape and texture.

• Meissner's corpuscles:

  • Rapidly-adapting receptors with relatively small receptive fields, but inferior spatial resolution compared to Merkel's discs.

  • Transmit information about movement between skin and surfaces to sense texture and detect object sliding to maintain grip.

• Pacinian corpuscles:

  • Rapidly-adapting receptors with very large receptive fields.

  • Transmit information about vibrations caused by contacting or grasping objects; important for using tools.

• Ruffini's endings:

  • Slowly-adapting receptors with large receptive fields.

  • Respond mainly to skin stretching to generate awareness of finger and hand position.