Contractile vacuole

A specialized vacuole of eukaryotic cells, especially Protozoa, that fills with water from the cytoplasm and then discharges this externally by the opening of contractile vacuole pores. Its function is probably osmoregulatory.

A contractile vacuole ('CV') is found in many cells. It pumps water in and out of the cell through osmoregulation. In this way regulates osmotic pressure.

Protist Paramecium aurelia with contractile vacuoles