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Reptile skin functions to protect from physical trauma, desiccation, infection, osmotic damage and extremes of temperature. There are several layers. The dermis is mainly connective tissue but contains the pigment cells. The epidermis is characterised by scales that are covered with keratin. The size and shape of scales varies greatly among species. The ventral scales (or scutes) are generally larger and thicker than the lateral and dorsal scales. The spectacle overlies the eye. The skin contains almost no glands and is shed (ecdysis) on a regular basis.
==Function and Morphology==
Reptile skin functions to protect from physical trauma, desiccation, infection, osmotic damage and extremes of temperature. There are several layers. The dermis is mainly connective tissue but contains the pigment cells. The epidermis is characterised by scales that are covered with keratin.
The skin of reptiles has numerous functions including display, protection, camouflage, thermoregulation and fluid homeostasis.
The skin is dry, with few glands compared with mammals and amphibians.
==Epidermis==
The epidermis consists of 3 layers:
* Stratum germinativum - which divides and produces keratin.
* Stratum intermedium - which contains lipid, thus preventing fluid loss.
* Stratum corneum - which forms scales and scutes.
In reptiles, 2 forms of keratin are present:
* Alpha-keratin which is flexible and often found between scales and scutes and in hinges.
* Beta-keratin which is unique to reptiles. It is harder than alpha-keratin and forms scutes and scales.
==Dermis==
The dermis of reptiles contains pigment cells, [[Snake Neurological System|nerves]] and vessels; however, thick, keratinised skin is without cutaneous sensation, leaving captive reptiles at risk of thermal burns.
* Find out more about [[Snake Vesicular Dermatitis|snake vesicular dermatitis (blister disease)]].
==Scales==
The size and shape of scales varies greatly among [[:Category:Snake Species|species]]: the [[Bushmaster|bushmaster]] has scales that are large with a dermal core or [[Osteoderm|osteoderm]] while they may be partially overlapping and keeled in the [[Rattlesnake|rattlesnake]]. The smallest scales are seen in the [[Boidae|boids]] and worm snakes. The ventral scales (or scutes) are generally larger and thicker than the lateral and dorsal scales.
==Glands==
Almost no skin glands occur in snakes, but [[Cloaca|coacal]] scent glands (anal glands) are present. They occur at the base of the tail, dorsal to the [[Hemipenes|hemipenes]] in a male, and open into the posterior margin of the cloaca. The unpleasant odour of these organs plays a defensive role and may also carry social signals. These may become enlarged, impacted, or abscessed in captivity.
==Skin adaptations and cutaneous appendages==
*[[Snake Eye|Spectacles]] - they are clear scales over the eyes of snakes.
*[[Snake Special Senses|Heat sensory pits]] (infrared-sensitive receptors) - they are deep grooves between the nares and the [[Snake Eye|eye]] of [[Pit viper|pit vipers]], [[Pythoninae|pythons]] and some [[Boidae|boas]] which allow them to 'see' the radiated heat of their prey. These pits can also be found on the upper lip, just below the nares, and are termed 'labial pits'.
*Rattle - it is present in some snakes and used to warn predators. It is enlarged with each [[Snake Shedding|shed]].
*Gastrosteges - they are a single row of large ventral scales in snakes that aid [[Snake Locomotion|locomotion]].
Also see: <big><b>[[Integument of Exotic Species - Anatomy & Physiology#Reptiles|Reptile Skin]]</b></big>
{{Learning
|full text = [http://www.cabi.org/cabdirect/FullTextPDF/2009/20093355673.pdf '''Reptilian dermatology.''' Wyneken, J.; Mader, D.; Baer, C. K.; Association of Reptilian and Amphibian Veterinarians, Chester Heights, USA, Proceedings of the Association of Reptilian and Amphibian Veterinarians, 16th Annual Conference, Milwaukee, Wisconsin, USA, 8-15 August, 2009, 2009, pp 83-87]
}}
==References==
Mader, D.R. (2005). Reptile Medicine and Surgery. Saunders. pp. 51 ISBN 072169327X
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[[Category:Snake_Anatomy]]