Editing Amphibian (section)

=== Nervous and sensory systems ===
{{see also|Pain in amphibians}}
The [[nervous system]] is basically the same as in other vertebrates, with a central brain, a spinal cord, and nerves throughout the body. The amphibian brain is relatively simple but broadly the same structurally as in reptiles, birds and mammals. Their brains are elongated, except in caecilians, and contain the usual motor and sensory areas of tetrapods.<ref>{{cite book|author1=González, A.|author2=López, J. M.|author3=Morona, R.|author4=Morona, N.|year=2020|chapter=The Organization of the Central Nervous System of Amphibians|title=Evolutionary Neuroscience|editor=Hass, J. H.|page=127|publisher=Elsevier Science |isbn= 978-0-12-820584-6}}</ref> The [[pineal body]], known to regulate sleep patterns in humans, is thought to produce the hormones involved in [[hibernation]] and [[aestivation]] in amphibians.{{sfn | Stebbins | Cohen | 1995 | p=100 }}

Tadpoles retain the lateral line system of their ancestral fishes, but this is lost in terrestrial adult amphibians. Many aquatic salamanders and some caecilians possess [[Electroreception|electroreceptors]] called ampullary organs (completely absent in anurans), that allow them to locate objects around them when submerged in water.<ref>[https://books.google.com/books?id=PpkvEAAAQBAJ&dq=salamanders+caecilians+ampullary+organs&pg=PA73 A Natural History of Amphibians]</ref> The ears are well developed in frogs. There is no external ear, but the large circular [[Tympanum (anatomy)|eardrum]] lies on the surface of the head just behind the eye. This vibrates and sound is transmitted through a single bone, the [[stapes]], to the inner ear. Only high-frequency sounds like mating calls are heard in this way, but low-frequency noises can be detected through another mechanism.{{sfn | Dorit | Walker | Barnes | 1991 | p=846 }} There is a patch of specialized haircells, called ''papilla amphibiorum'', in the inner ear capable of detecting deeper sounds. Another feature, unique to frogs and salamanders, is the columella-operculum complex adjoining the auditory capsule which is involved in the transmission of both airborne and seismic signals.{{sfn | Stebbins | Cohen | 1995 | p=69 }} The ears of salamanders and caecilians are less highly developed than those of frogs as they do not normally communicate with each other through the medium of sound.<ref name="EBAmphibia" />

The eyes of tadpoles lack lids, but at metamorphosis, the [[cornea]] becomes more dome-shaped, the [[Lens (anatomy)|lens]] becomes flatter, and [[eyelid]]s and associated glands and ducts develop.{{sfn | Dorit | Walker | Barnes | 1991 | p=846 }} The adult eyes are an improvement on invertebrate eyes and were a first step in the development of more advanced vertebrate eyes. They allow colour vision and depth of focus. In the retinas are green rods, which are receptive to a wide range of wavelengths.<ref name="EBAmphibia">{{cite encyclopedia |url=https://www.britannica.com/EBchecked/topic/21445/amphibian/ |title=Amphibian |author1=Duellman, William E. |author2=Zug, George R. |year=2012 |encyclopedia=Encyclopædia Britannica |access-date=March 27, 2012 |archive-date=March 8, 2012 |archive-url=https://web.archive.org/web/20120308183351/https://www.britannica.com/EBchecked/topic/21445/amphibian |url-status=live }}</ref>