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

The rate at which a Paramecium's contractile vacuole contracted to pump out excess water was determined and plotted against osmolarity of the solutions, as shown in the graph.

From Textbooks • Jun. 9, 2022

The contractile vacuole is less efficient in solutions of high osmolarity because of the reduced amount of ATP produced from cellular respiration.

From Textbooks • Jun. 9, 2022

Cells remove water by means of a contractile vacuole and exocytosis.

From Textbooks • Jan. 1, 2018

The contractile vacuole is terminal, the proboscis is short, slightly raised and separated from the body by a deep cleft; the buccal cilia are inserted part way up on the proboscis.

From Marine Protozoa from Woods Hole Bulletin of the United States Fish Commission 21:415-468, 1901 by Calkins, Gary N. (Gary Nathan)

The nucleus is minute and lateral in position; the contractile vacuole is in the posterior end of the body.

From Marine Protozoa from Woods Hole Bulletin of the United States Fish Commission 21:415-468, 1901 by Calkins, Gary N. (Gary Nathan)