http://media-2.web.britannica.com/eb-media/68/8968-004-A94DB3DF.jpg (Picture of a Trichocyst)
A trichocyst is a structure in the cortex of certain ciliate and flagellate protozoans consisting of a cavity and long, thin threads that can be ejected in response to certain stimuli. Trichocysts may be widely distributed over an organism or restricted to certain areas. They are characteristics of the Phylum Ciliophora.
In ciliates and dinoflagellates, the trichocyst is an organelle that releases long filamentous proteins that capture prey in "nets" to slow them down when the cell is disturbed. The protein is nontoxic and shaped like a long, striated, fibrous shaft.
It may also be used to anchor the protozoa while it is feeding or capture food to bring into itself. In Paramecium, it is almost certain that the anchorage function is the correct one.
The trichocyst is shaped like a hollow cavity filled with long, thin threads of protein. Trichocysts may be found in only one area, like around the tentacles or mouth, or it may be found all over the organism. Different types of trichocysts seem to have different functions. The Paramecium filamentous trichocysts have filaments that are similar to harpoons: a long filament with a cross-striated shaft and a tip. Trichocysts for toxicysts tend to be around the mouth, where the toxin can be shot out to paralyze or kill other microorganisms.
A trichocyst can be found in tetrahymena and along cila pathways of several metabolic systems.
