A cutaneous receptor is a sensory receptor found in the skin that provides information about temperature, touch (including vibration and pain), spatial orientation,pressure (stretching or squeezing), and metabolic circumstances (including those induced by external chemical substances). The main four types of cutaneous receptors are tactile corpuscles, bulbous corpuscles, Pacinian corpuscles, and Merkel nerve endings, although the latter do not qualify as sensory corpuscles in the narrow sense.[1]
Types
editThe sensory receptors in the skin are:
- Mechanoreceptors
- Bulbous corpuscles (skin stretch)
- Bulboid corpuscles (Cold)
- Tactile corpuscles (changes in texture, slow vibrations)
- Pacinian corpuscles (deep pressure, fast vibrations)
- Merkel nerve endings (sustained touch and pressure)
- Free nerve endings
- thermoreceptor
- nociceptors
- chemoreceptors
Modalities
editWith 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.
| Modality | Type | Fiber type |
|---|---|---|
| Touch | Rapidly adapting cutaneous mechanoreceptors (tactile corpuscles Pacinian corpuscles hair follicle receptors some free nerve endings) |
Aβ fibers |
| Touch and pressure | Slowly adapting cutaneous mechanoreceptors (Merkel nerve ending and bulbous corpuscles some free nerve endings) |
Aβ fibers (Merkel and Ruffini's), Aδ fibers (free nerve endings) |
| Vibration | Tactile corpuscles and Pacinian corpuscles | Aβ fibers |
| Temperature | Thermoreceptors | Aδ fibers (cold receptors) C fibers (warmth receptors) |
| Pain and Itch | Free nerve ending nociceptors | Aδ fibers (Nociceptors of neospinothalamic tract) C fibers (Nociceptors of paleospinothalamic tract) |
Morphology
editCutaneous receptors are at the ends of afferent neurons. works 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, the ventrobasal portion of the thalamus, and then on to the somatosensory cortex.[2]
See also
editReferences
edit- ^ Cobo, Ramón; García-Piqueras, Jorge; Cobo, Juan; Vega, José A. (2021-01-10). "The Human Cutaneous Sensory Corpuscles: An Update". Journal of Clinical Medicine. 10 (2): 227. doi:10.3390/jcm10020227. ISSN 2077-0383. PMC 7827880. PMID 33435193.
- ^ Mada S. S. (2000): Human Biology. McGraw–Hill, New York, ISBN 0-07-290584-0.