Editing Chondrichthyes (section)

===Nervous system===
[[File:Skate Brain Regions.png|thumb|Regions of a Chondrichthyes brain colored and labeled on dissected skate. The [[Anatomical terms of location#Cranial and caudal|rostral]]{{Broken anchor|date=2025-03-24|bot=User:Cewbot/log/20201008/configuration|target_link=Anatomical terms of location#Cranial and caudal|reason= The anchor (Cranial and caudal) [[Special:Diff/1175671216|has been deleted]].|diff_id=1175671216}} end of the skate is to the right.]]
In chondrichthyans, the nervous system is composed of a small brain, 8–10 pairs of cranial nerves, and a spinal cord with spinal nerves.<ref>{{Cite journal|last=Collin|first=Shaun P.|date=2012|title=The Neuroecology of Cartilaginous Fishes: Sensory Strategies for Survival|journal=Brain, Behavior and Evolution|language=en|volume=80|issue=2|pages=80–96|doi=10.1159/000339870|pmid=22986825|s2cid=207717002|issn=1421-9743}}</ref> They have several sensory organs which provide information to be processed. [[Ampullae of Lorenzini]] are a network of small jelly filled pores called [[Electroreception|electroreceptors]] which help the fish sense electric fields in water. This aids in finding prey, navigation, and sensing temperature. The [[lateral line]] system has modified epithelial cells located externally which sense motion, vibration, and pressure in the water around them. Most species have large well-developed eyes. Also, they have very powerful nostrils and [[Olfactory bulb|olfactory]] organs. Their inner ears consist of 3 large [[semicircular canals]] which aid in balance and orientation. Their sound detecting apparatus has limited range and is typically more powerful at lower frequencies. Some species have [[Electric organ (biology)|electric organs]] which can be used for defense and predation. They have relatively simple brains with the forebrain not greatly enlarged. The structure and formation of myelin in their nervous systems are nearly identical to that of tetrapods, which has led evolutionary biologists to believe that Chondrichthyes were a cornerstone group in the evolutionary timeline of myelin development.<ref>{{Cite journal|last=de Bellard|first=Maria Elena|date=2016-06-15|title=Myelin in cartilaginous fish|journal=Brain Research|volume=1641|issue=Pt A|pages=34–42|doi=10.1016/j.brainres.2016.01.013|issn=0006-8993|pmc=4909530|pmid=26776480}}</ref>