contractile vacuole

American  

noun

Cell Biology.

1. a membrane-enveloped cellular organelle, found in many microorganisms, that periodically expands, filling with water, and then contracts, expelling its contents to the cell exterior: thought to be important in maintaining hydrostatic equilibrium.

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Etymology

Origin of contractile vacuole

First recorded in 1875–80

Example Sentences

Finally, at :51 you see a special star-burst shaped organelle called the contractile vacuole in action.

From Scientific American

As one would expect of a freshwater species, Microgromia has a contractile vacuole complex that gradually expands as its components fill up and fuse, and then expels its contents somehow — this appears to happen inside the test.

From Scientific American

In some protists, the contractile vacuole simply fuses with the membrane and expels its contents, but there are also plenty of variations on the subject.

From Scientific American

Actinophrys sol, Ehrb. a, food-particle lying in a large food-vacuole; b, deep-lying finely granular protoplasm; c, axial filament of a pseudopodium extended inwards to the nucleus; d, the central nucleus; e, contractile vacuole; f, superficial much vacuolated protoplasm.

From Project Gutenberg

Raphidiophrys pallida, F. E. Schultze. a, food-particle; b, contractile vacuole; c, the nucleus; d, central granule in which all the axis-filaments of the pseudopodia meet.

From Project Gutenberg