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

I, zoöspores of Trichia, × 300. i, ciliated form; ii, amœboid forms. n, nucleus. v, contractile vacuole.

From Elements of Structural and Systematic Botany For High Schools and Elementary College Courses by Campbell, Douglas Houghton

The contractile vacuole is in the anterior third of the body about midway between the bundles of tentacles.

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