Spiracle
- Spiracle
Spiracles are small openings on the surface of some animals that usually lead to respiratory systems.
In elasmobranchs (sharks and rays), a spiracle is found behind each eye, and is often used to pump water through the gills while the animal is at rest (Fouts, 2003). A spiracle is also found in primitive bony fishes as the chirrups.
piracles in insects
Insects and some more advanced spiders have spiracles on their exoskeletons to allow air to enter the trachea (Solomon et al., 2002). In insects, the tracheal tubes primarily deliver oxygen directly the animals' tissues. The spiracles can be opened and closed in an efficient manner to reduce water loss. This is done by contracting closer muscles surrounding the spiracle. In order to open, the muscle relaxes. The closer muscle is controlled by the central nervous system but can also react to localized chemical stimuli. Several aquatic insects have similar or alternative closing methods to prevent water from entering the trachea. In spiders, however, the oxygen diffuses into the hemolymph (Foelix, 1996). A similar diffusion effect also occurs in some insect caterpillars. In these groups the respiration is more reminiscent of lungs. In spiders and other arachnids they have structures called book lungs.
References
* Fouts, William. April 2003. Marine Science Dept. Orange Coast College.
* Solomon, Eldra, Linda Berg, Diana Martin. 2002. "Biology". Brooks/Cole.
* Foelix, Ranier. 1996. "Biology of Spiders". Oxford U. Press
* Chapman, R. F. "The Insects". 1998. "Cambridge University Press"
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spiracle — [ spirakl ] n. m. • 1924; « soupirail » XVIe; lat. spiraculum ♦ Zool. Orifice de sortie de l eau qui a baigné les branchies, chez les têtards de batraciens anoures. ● spiracle nom masculin (latin spiraculum) Orifice de sortie de l eau qui a… … Encyclopédie Universelle
Spiracle — Spir a*cle, n.[L. spiraculum, fr. spirare to breathe: cf. F. spiracule. See {Spirit}.] 1. (Anat.) The nostril, or one of the nostrils, of whales, porpoises, and allied animals. [1913 Webster] 2. (Zo[ o]l.) (a) One of the external openings… … The Collaborative International Dictionary of English
spiracle — “air hole,” 1610s, from L. spiraculum, from spirare “to breathe” (see SPIRIT (Cf. spirit)) … Etymology dictionary
spiracle — ► NOUN Zoology ▪ an external respiratory opening in insects, cartilaginous fish, and other animals. DERIVATIVES spiracular adjective. ORIGIN Latin spiraculum, from spirare breathe … English terms dictionary
spiracle — [spir′ə kəl, spī′rəkəl] n. [ME < L spiraculum < spirare, to breathe: see SPIRIT] 1. a small opening allowing the outer air to come through into a confined space; air hole 2. Geol. a small vent formed on the surface of a thick lava flow 3.… … English World dictionary
spiracle — spiracular /spuy rak yeuh leuhr, spi /, adj. /spuy reuh keuhl, spir euh /, n. 1. a breathing hole; an opening by which a confined space has communication with the outer air; air hole. 2. Zool. a. an aperture or orifice through which air or water… … Universalium
spiracle — noun Etymology: Middle English, from Latin spiraculum, from spirare to breathe Date: 15th century 1. a breathing hole ; vent 2. a breathing orifice: as a. blowhole 2 b. an external tracheal aperture of a terrestrial arthropod that in an insect is … New Collegiate Dictionary
spiracle — a vestigial gill cleft between the eye and the gill slits in Elasmobranchii, Acipenseridae, Polyodontidae, and Polypteridae. Water for respiration is inhaled through the spiracles in Rajiformes. Connects with the gill cavity; often retains… … Dictionary of ichthyology
spiracle — n. [L. spirare, to breathe] (ARTHROPODA) A breathing pore or orifice leading to the tracheal or respiratory system; stigma; spiracular adj … Dictionary of invertebrate zoology
spiracle — noun /ˈspɪrəkəl/ a) A pore or opening used (especially by spiders and some fish) for breathing. b) The blowhole of a whale … Wiktionary
