Phaosome

The phaosome ( ancient Greek φάος pháos "light" and σῶμα sō̂ma "body") is a vacuole located in the light cells of various salps , annelids and molluscs , which is associated with the visual process .

The phaosome is filled with a hyaline mass. On the inside of the membrane of the phaosome there are numerous microvilli adjoining this mass and in many cases protruding into it , which have the structure of rhabdomers in the arthropod's complex eyes . It is assumed that a reversible chemical reaction takes place in the hyaline mass when exposed to light.

Phaosomen are in the eye or even individual photoreceptor cells of annelids - including earthworms , pond snakes , leeches and the marine polychaete Terebella lapidaria - and snails so on - brackish pond snails (genus Potamides been found -). The shape of the phenomena is often species-specific to the extent that it can be used to determine the species . This is the case with earthworms, for example.

literature

• August Pütter: Organology of the eye. J. Bergmann, Wiesbaden 1912. Light sense cells with phaosome , pp. 105-108.
• Dominik Kieselbach: Investigations on the phylogeny of sedentary polychaetes (Annelida). Doctoral thesis, Bonn 2012.

Web links

• Phaosome. In: Lexicon of Biology , online edition, 1999.