gill


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gill

(gĭl)
n.
Zoology The respiratory organ of most aquatic animals that obtain oxygen from water, consisting of a filamentous structure of vascular membranes across which dissolved gases are exchanged.

gilled adj.

gill

  1. the respiratory organ of aquatic animals. External gills, as in tadpoles, are produced by the embryonic ECTODERM; internal gills, as in fish, are developed from the pharynx and are thus endodermal (see ENDODERM). Gills are usually well supplied with blood vessels, and interchange of oxygen and carbon dioxide takes place across the extensive surface area (see COUNTERCURRENT EXCHANGE). Gills also occur in many invertebrates, for example, in insects such as the caddis fly larva and molluscs such as oysters. Occasionally, unusual structures act as gills, for example, the walls of the rectum in certain dragonfly nymphs, water being pumped in and out via the anus.
  2. the spore-carrying lamellae in basidiomycete fungi, located underneath the cap or ‘pileus’.

gill

external breathing apparatus of fish. Very susceptible to a wide range of diseases.
Enlarge picture
Gill system of fish. By permission from Aspinall V, O'Reilly M, Introduction toVeterinary Anatomy and Physiology, Butterworth Heinemann, 2004

gill disease
an infectious disease of aquarium and salmonid species of fish caused by Flavobacterium bronchiophila. Also in Crassostrea angulata caused by an iridovirus and in larval shrimp caused usually by a Leucothrix spp. bacterium. Chronic, proliferative inflammation causes the gill filaments to be swollen and may be clubbed or fused. Called also bacterial gill disease.
gill parasites
the following external parasites are commonly found on the gills, and elsewhere on the skin, in aquarium fish: Gyrodactylus elegans—a monogenetic fluke; Diplozoon barbi, D. paradoxum—monogenetic flukes; Ergasilus sieboldi—crustaceans. Freshly caught seahorses may carry the crustacean Argulus spp. Pond fish may carry the anchor worm Lernaea spp. These are all visible with the naked eye and can be removed manually.
References in periodicals archive ?
In September 2014, Gill was over the moon after being phoned out of the blue by Helen, who had recently got married in a vineyard.
Mr Powell said Mr Gill is currently on hol- Essay: Page 18
On March 8, 2016, during a safety inspection at the Massena, New York Port of Entry, Gill was again ordered out-of-service for falsifying records-of-duty status.
Each week, Gill walks her sheep through Parkgate, often along the Parade, and they have become a part of the local community.
The model Gills has invested in was only launched this year and has the added benefit of a triple oil filtration system.
Keogh denies attempting to murder Albert Gill and wounding him with intent to cause grievous bodily harm.
Gill, husband Andrew, Jackie and Craig are going on the Ride The North bike run from Inverness to Aberdeen on August 30 and 31 to raise cash for the Sandpiper Trust so they can train more emergency responders.
Gill is a college graduate and is working a full-time job, according to Mr.
Ferguson added if he could have found a way of persuading Gill to stay then he would love to have done that.
Jurors heard that wheelchair-bound Gill told his victims he had been an Army doctor but he had no medical qualifications.