a hollow structure that alternately contracts and expands, as found in amebae, paramecia, and so forth
Source: Noland, George B. 1983. General Biology, 11th Edition. St. Louis, MO. C. V. Mosby ...
contractile vacuole -- In many protists, a specialized vacuole with associated channels designed to collect excess water in the cell. Microtubules periodically contract to force this excess water out of the cell, regulating the cell's osmotic balance.
An organelle that pumps excess water out of many freshwater protist cells.
contractile vacuole Organelle in many eukaryotes that acts as a bilge pump in the active transport of excess water from the cell.
contrast In relation to microscopes, the ability to distinguish different densities of structures.
Contractile vacuoles are organelles in the cells of sponges and freshwater protozoans. In the freshwater Amoeba proteus, for example, the bubble-like contractile vacuole swells with excess fluid from the cytoplasm .
~ an organelle found in some single-celled organisms which removes excess water from the cell.
Corolla a collective name for the petals of a flower.
Coronary heart disease the blockage of one or more of the coronary arteries which supply blood to the muscle of the heart.
~ A clear fluid-filled cell vacuole in protozoa and a few lower metazoa; takes up water and releases it to the outside in a cyclical manner, for osmoregulation and some excretion.
A ~ is used to pump excess water out of the cell to reduce osmotic pressure and keep the cell from bursting. ~s are found in some freshwater protozoa.
Vacuoles in plant cells: the central vacuole ...
Most Ciliates contain a ~ to help maintain homeostasis. A common example of a Ciliate is the Paramecium. The Paramecium has a very unusual way of creating genetic variety. It has both a micronucleus and a macronucleus filled with genetic information.
Fresh water ciliates cope with the continuous influx of water from their hypotonic surroundings by pumping it out with one or more ~s. Parasitic ciliates, which live in isotonic surroundings, have no ~.
Amoeba make use of ~s to collect excretory waste, such as ammonia, from the intracellular fluid by both diffusion and active transport.
Some cells, such as Paramecium have organelles called ~s which are basically little pumps which pump excess water out of cell
You can alter the rate of ~ pumping by placing it in increasingly hypotonic solutions ...
Water accumulates within the ~, a membrane-bounded structure, which inflates.
To expel the water, the vacuole connects with the plasma membrane and is squeezed by cytoskeletal systems within the cytoplasm.
Food vacuoles are formed by phagocytosis and fuse with lysosomes.
~s, found in freshwater protists, pump excess water out of the cell to maintain the appropriate concentration of salts.
A large central vacuole is found in many mature plant cells.
Sequences show the motility of this ciliated protozoan and the repetitious activity of both anterior and posterior ~s.
5.4 Spirostomum (ciliated protozoa)
Though they look a bit like worms, these are ciliates that move with a gentle gliding motility.
See also: What is the meaning of Vacuole, Organ, Membrane, Cells, Animal?