Lorenzini ampoules

from Wikipedia, the free encyclopedia
Lorenzini ampoules on the underside of a shark's head

The Lorenzini ampoules are sensory organs under the skin on the head of sharks , rays and sea ​​cats , which mainly enable the perception of electrical fields and temperature differences. The sensitivity to electric fields is about 10  n V (10 -8 volts ) about 1 cm sea water, for temperature differences at 0.2  K .

The perception of electrical fields is used to locate the prey at the last moment of the attack. Before that, the animals tend to orientate themselves to other senses.

Furthermore, the Lorenzini ampoules are likely to be of great importance for orientation towards the earth's magnetic field . This also explains the large populations observed especially in whale sharks and hammerhead sharks , which take place at certain locations at the same time for mating purposes.

The Lorenzini ampoules are visible to the naked eye as dark pore openings.

construction

There are many pores on the scalp surface that form an opening to the gelatin-filled tubules. These tubes can be several inches long. At the end of the canal there is an ampoule with the sensory cells that serve as electroreceptors and are connected to the shark's nervous system.

Explorer

The Italian Marcello Malpighi discovered the Lorenzini ampoules in 1663. They were first described in detail in 1678 by the Italian doctor Stefano Lorenzini (* after 1652, † after 1700) in his Osservazioni intorno alle torpedini (probably written together with Francesco Redi ) . In honor of Lorenzini, this sense organ, which gives the shark a "sixth sense", was named after him.

literature

  • Neil Campbell, Jane Reece: Biology. 6th edition. Spektrum Akademischer Verlag, Berlin 2003, ISBN 3-8274-1352-4 .
  • Vitus Dröscher: Sharks and rays . (= What is what. Volume 95). Tessloff Verlag, Nuremberg 1993, ISBN 3-7886-0637-1 .
  • R. Douglas Fields: The Shark's Sixth Sense. In: Spectrum of Science. 11/2007, p. 55ff.

Individual evidence

  1. ↑ a b R. Douglas Fields: The sixth sense of the sharks. In: Spectrum of Science. 11/2007, p. 55 ff.
  2. ^ Luigi Guerrini: Contributo critico alla biografia rediana, con uno studio su Stefano Lorenzini e le sue "Osservazioni intorno alla Torpedini". In: Walter Bernardi, Luigi Guerrini (eds.): Francesco Redi, un protagonista della scienza moderna. Documenti, esperimenti, immagini . LS Olschki, Florence 1999, ISBN 88-222-4719-1 .
  3. ^ Stefano Lorenzini: Osservazioni intorno alle torpedini . Onofri, Florence 1678. ( GBS )

Web links