Cutaneous receptor

A cutaneous receptor is a type of sensory receptor found in the dermis or epidermis. They are a part of the somatosensory system. Cutaneous receptors include e.g. cutaneous mechanoreceptors, nociceptors (pain) and thermoreceptors (temperature).

Types

The sensory receptors in the skin are:

• cutaneous mechanoreceptors
• Ruffini's end organ (sustained pressure)
• Meissner's corpuscle (changes in texture, slow vibrations)
• Pacinian corpuscle (deep pressure, fast vibrations)
• Merkel's disc (sustained touch and pressure)
• Free nerve endings
• thermoreceptor
• nociceptor
• bulboid corpuscles
• chemoreceptor

Modalities

With the above mentioned receptor types the skin can sense the modalities touch, pressure, vibration, temperature and pain. The modalities and their receptors are partly overlapping, and are innervated by different kinds of fiber types.

Cutaneous receptors

Modality	Type	Fiber type
Touch	Rapidly adapting cutaneous mechanoreceptors (Meissner corpuscle end-organs Pacinian corpuscle end-organs hair follicle receptors some free nerve endings)	Aβ fibers
Touch & pressure	Slowly adapting cutaneous mechanoreceptors (Merkel and Ruffini corpuscle end-organs some free nerve endings)	Aβ fibers (Merkel and Ruffini's), Aδ fibers (free nerve endings)
Vibration	Meissners and Pacinian corpuscle end-organs	Aβ fibers
Temperature	Thermoreceptors	Aδ fibers (cold receptors) C fibers (warmth receptors)
Pain	Free nerve ending nociceptors	Aδ fibers (Nociceptors of neospinothalamic tract) C fibers (Nociceptors of paleospinothalamic tract)

Morphology

Cutaneous receptors are at the ends of afferent neurons. They are usually encapsulated in elaborate cellular corpuscles. Generally, they are linked to collagen-fibre networks within the capsule. Ion channels are situated near these networks.

In sensory transduction, the afferent nerves transmit through a series of synapses in the central nervous system, first in the spinal cord or trigeminal nucleus, depending on the dermatomic area concerned. One pathway then proceeds to the ventrobasal portion of the thalamus, and then on to the somatosensory cortex.