Book lung

Book lungs, " lung compartments " or " Fächertracheen " are the respiratory organs of spiders and scorpions, beside Röhrentracheen and skin.

The book lungs are always on the front ventral ( " belly ") of the opisthosoma (abdomen), paired left and right of the body midline. The respiratory openings ( stigmata ) are slots which are formed by the rear edge of the hairless lung lid. The lung lid can be moved by muscle contraction and increase the stigmata. The Stigmata rich inside the body, where they form the breath atrial formed from a thin cuticle layer. From the breath atrial rich with limited cuticle invaginations, respiratory bags, horizontally in a container filled with hemolymph cavity, the pulmonary sinus. The breathing bags are prevented by Cuticulasäulen from collapsing. Because of the structure of the stacked bags is referred to as book breathing lungs or subjects lungs. The cuticle layer is formed from the Hypodermislamellen.

Almost all of the hemolymph must pass on their way back to the heart of the book lungs. From the prosoma ( front body ) the hemolymph flows through two lateral cavities ( lacunae ) in the petiole in the pulmonary sinus in the foremost part of the opisthosoma. In the pulmonary sinus also open lacunae from the rear of the opisthosoma. From the pulmonary sinus in the middle of the body, the haemolymph flows sideways between the breathing bags. The thin cuticle layer and Hypodermislamellen through oxygen diffuses. The oxygenated hemolymph flows on the sides by a further ascending pulmonary sinus up to the heart. A ventilation probably does not occur, apparently sufficient diffusion of the uptake of oxygen.

Presumably, the Röhrentracheen from the Fächertracheen have developed. The latter are often found in smaller spiders. The " primitive " members spiders, tarantulas and Family Hypochilidae have two pairs of book lungs in the second and third abdominal segment. For most genuine spiders, the second pair is converted to Röhrentracheen. The Fächertracheen same at all spiders in the building; Röhrentracheen the other hand, are diversified diverse. Whether book lungs or Röhrentracheen play the major role is not clearly say in the diversity of spiders. In the water spider, for example, the book lungs are reduced, both pairs appear at the Caponiidae as filter or Röhrentracheen, Aspen spiders ( Pholcidae ) only have a couple book lungs, Symphytognathidae have only one pair of seventh Racheen on.

Swell

  • Rainer F. Foelix: Biology of spiders. Georg Thieme Verlag, Stuttgart 1979. ISBN 3- 13-575801 -X
  • Anatomy (eddy lots)
  • Arachnologie
  • Breathing apparatus
Petiole (insect anatomy) Ventilation (physiology)
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