gill

(redirected from Ghyll)
Also found in: Dictionary, Thesaurus, Legal, Financial, Encyclopedia, Wikipedia.

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 ?
It was a bold move by Holbeck Ghyll to allow the BBC to set a large chunk of one of the episodes in its splendidly English oak-panelled restaurant.
Holbeck Ghyll has so far managed this very well, the more modern cottages and suites in the grounds not clashing with the main house.
He was just 5lb lower that day and given that Balding's yard is in excellent form at present, Holbeck Ghyll merits maximum respect.
Ashington High School student Daniel Kelly assists the group during ghyll scrambling on the annual visit to |Ullswater Outward Bound Centre in the Lake District
Passing through the metal gate we follow the pathway as it twists and turns down the delightful woodland and over several foot bridges to join Hebers Ghyll Drive.
Together they claimed a handful of minor successes with a handicap hurdler called Heron's Ghyll, named after her home village.
00pm) Carl puts his plan to raid Cain's warehouse into action, but his scheme hits a snag when Charity catches him breaking into Tug Ghyll.
However, Sarah wanders off when Victoria's back is turned but is found by Aaron, who takes the youngster to Tug Ghyll.
Holbeck Ghyll, also in Windermere, was built in the 19th Century and was a former hunting lodge for Lord Lonsdale.
Carl lends Debbie the money to buy Tug Ghyll, to spite Matthew, and Nicola tries to literally scare Donald to death.
The five-year-old was value for a lot more when coming home 26 lengths clear of Heron's Ghyll in a novice hurdle over two miles one and a half furlongs.