Ampullae of Lorenzini

The ampullae of Lorenzini are the sense organs under the skin on the head of sharks, rays and chimaeras, which mainly target the perception of electric fields and temperature differences. The sensitivity to electric fields is 10 nV ( 10-8 volts) over 1 cm seawater for temperature differences of 0.2 ° C.

The perception of electric fields is used to locate the prey at the last moment of the attack. Prior to the animals orient more on other senses.

Furthermore, should the ampullae of Lorenzini of the orientation on the earth's magnetic field be of great importance. It thus could be explained the observed especially in whale sharks and hammerheads large gatherings that take place to pairing purposes in certain places at the same time.

The ampullae of Lorenzini are visible to the naked eye as a dark pore openings.

Construction

On the scalp surface, there are many pores that form an opening to the jelly- filled canals. These tubes can be several inches long. At the end of the channel there is a vial containing the sensory cells, which serve as electrical receptors and are connected to the nervous system of the shark.

Discoverer

The Italian Marcello Malpighi discovered the ampullae of Lorenzini in 1663 described in detail the first time they were in 1678 by the Italian physician Stefano Lorenzini ( * after 1652; † after 1700). In his (probably co-authored with Francesco Redi ) Osservazioni intorno all torpedini. Lorenzini honor was named this sense organ that gives a "sixth sense" the shark after him.