Cutaneous receptor
A cutaneous receptor is the type of sensory receptor found in the skin ( the dermis or epidermis). They are a part of the somatosensory system. Cutaneous receptors include mechanoreceptors (pressure or distortion), nociceptors (pain), and thermoreceptors (temperature).[1]
Types
[edit]The 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
[edit]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.
| 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
[edit]Cutaneous 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
[edit]References
[edit]- ^ Lincoln R. J., Boxshall G. A. (1990): Natural history - The Cambridge illustrated dictionary. Cambridge University Press, Cambridge, ISBN 0 521 30551-9.
- ^ Mada S. S. (2000): Human Biology. McGraw–Hill, New York, ISBN 0-07-290584-0.