Electroreception in Sharks

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Heather Capp Dr. Campese Psych 300 October 20, 2012 Electroreception in Sharks Electroreception is an acute sensitivity to bioelectric fields found primarily in aquatic vertebrates as either a passive or active skill. Electroreceptive animals make use of weak electric currents chiefly to locate objects around them, particularly prey .This ability can also be used to avoid predation and in geomagnetic navigation. Sharks, like other members of the Elasmobranch family, possess electroreceptors called ampullae of Lorenzini, which are scattered over their heads in distinct clusters. They are an extension of the lateral line, which is a long, hollow sensory organ stretching down sharks’ sides from gill to tail with perforated scale openings, allowing the sharks to sense water pressure, direction, and displacement. Ampullae of Lorenzini are used in passive electroreception, which utilizes the animate and inanimate electric fields generated by the activity of nerves and muscles in other animals in order to detect them. The ampullae of Lorenzini are able to measure minute changes in potential between water at the surface of the skin and at the basal surface of receptor cells. Each ampulla consists of an elongated epithelial canal opening to a skin pore at one end and terminating below the surface of the epidermis in a cluster of receptor cell-containing alveoli at the other. These alveoli can be home to thousands of receptor cells interspersed with supportive cells in a single cluster. Underneath the receptor cells reside up to 15 afferent nerve fibers contacting or innervating a single alveolus. By way of the canal, which is formed of tightly joined squamous epithelial cells, the receptor cells can communicate with the water surrounding the shark. The canal is filled with an electrically conductive mucopolysaccharide jelly. The canal itself can vary in length between

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