Rhabdom

Rhabdom

Rhabdoms are transparent rods, found in the center of each ommatidium in the compound eye of arthropods. These rods are constructed from the eight photoreceptor cells in the ommatidium. Each photocell is long and thin. They pack their area of the ommatidium completely filling the space. The part of each photocell nearest the central axis of the ommatidium fuses with the other photocells and collectively they form the rhabdom. The rhabdom acts as a light guide, to enhance the detection of the photons entering the ommatidium.

The rhabdom is the photoreceptor light-sensing organelle and is the functional equivalent of the outer segment of vertebrate rod and cone cells. Each R cell contributes one rhabdomere to the composite rhadom. One rhabdomere consists of 60,000 tightly-packed microvilli, each 50 nm in diameter and 1-2 µm in length. This results in a tremendous increase in surface area to house the tens of millions of rhodopsin molecules and associated signaling molecules that are responsible for the detection of light. (From Greek word "rhabdma", "rhabdos", rod).

External links

* [http://xray.optics.rochester.edu/workgroups/cml/opt307/spr04/greg/ Example pictures]


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Look at other dictionaries:

  • Rhabdom — Rhab dom (r[a^]b d[o^]m), n. [Gr. ra bdwma a bundle of rods, fr. ra bdos a rod.] (Zo[ o]l.) One of numerous minute rodlike structures formed of two or more cells situated behind the retinul[ae] in the compound eyes of insects, etc. See Illust.… …   The Collaborative International Dictionary of English

  • Rhabdom — ⇒ Ommatidium …   Deutsch wörterbuch der biologie

  • rhabdom — rhabdomal /rab doh meuhl, rab deuh meuhl/, adj. /rab deuhm, dom/, n. Anat., Zool. 1. any of various rod shaped structures. 2. the rod shaped portion of an arthropod ommatidium. Also, rhabdome /rab dohm/. [1875 80; < LGk rhábdoma bundle of rods;… …   Universalium

  • Rhabdom — Das Rhabdom (von griech. rhabdos = „Rute, Stab“) ist der lichtleitende Achsstab innerhalb eines Ommatidiums des Komplexauges, oder eines Punktauges (Ocellus) eines Gliederfüßers. Es wird durch die 5 bis 9 Mikrovillisäume der Retinulazellen, auch… …   Deutsch Wikipedia

  • Rhabdom — Rhab|dom 〈n. 11〉 stabförmiges Organ in den Sehzellen von Komplexaugen [zu grch. rhabdos „Stab“] * * * Rhab|dom, das; s, e [zu griech. rhábdos = Stab, Rute] (Anat.): ↑ Stäbchen (3) u. ↑ Zapfen (6) in der Netzhaut des Auges. * * * Rhabdo …   Universal-Lexikon

  • rhabdom — or rhabdome noun Etymology: New Latin, from Late Greek rhabdōma bundle of rods, from Greek rhabdos rod Date: 1878 one of the minute rodlike structures in the retinulae in the compound eyes of arthropods …   New Collegiate Dictionary

  • rhabdom — n. [Gr. rhabdos, rod] (ARTHROPODA) A rodlike light sensitive structure formed by rhabdomeres in the ommatidium of a compound eye …   Dictionary of invertebrate zoology

  • rhabdom — noun Any of the rods that support each ommatidium in the compound eye of arthropods …   Wiktionary

  • Rhabdom — Rhab|dom 〈n.; Gen.: s, Pl.: e; Zool.〉 stabförmiges Organ in den Sehzellen von Facettenaugen [Etym.: <grch. rhabdos »Stab«] …   Lexikalische Deutsches Wörterbuch

  • Rhabdom — Rhabdo̱m [zu gr. ϱ̔αβδος = Rute, Gerte, Stab] s; s, e: allg. Bez. für die Stäbchen und Zapfen in der Netzhaut des Auges …   Das Wörterbuch medizinischer Fachausdrücke

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