Indian moon moth (Actias selene) with some of the spiracles identified

Spiracles are small openings on the surface of some animals that usually lead to respiratory systems. The Indian Moon Moth or Indian Luna Moth ( Actias selene) is a species of moth In living organisms a respiratory system functions to allow Gas exchange.

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). Elasmobranchii is the subclass of Cartilaginous fish that includes Skates rays (batoidea, and sharks (selachii. Sharks ( Superorder Selachimorpha) are a type of Fish with a full cartilaginous Skeleton and a highly streamlined body Batoidea is a Superorder of cartilaginous fish containing more than 500 described species in thirteen families Eyes are organs that detect Light, and send signals along the Optic nerve to the visual areas of the brain For information on Wikipedia project-related discussions see WikipediaVillage pump. A gill is an anatomical structure found in many aquatic organisms A spiracle is also found in primitive bony fishes as the chirrups.

Spiracles in insects

Insects and some more advanced spiders have spiracles on their exoskeletons to allow air to enter the trachea (Solomon et al. Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described Spiders are Predatory Invertebrate Animals that have two body segments, eight legs no chewing mouth parts and no wings An exoskeleton is an external Skeleton that supports and protects an animal's body in contrast to the internal Endoskeleton of for example a Human. Many terrestrial Arthropods have evolved a closed Respiratory system composed of Spiracles, tracheae and Tracheoles to transport metabolic , 2002). However, the two groups differ in how the tracheae function: in insects, the tracheal tubes primarily deliver oxygen directly to the animals' tissues. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Tissue is a cellular organizational level intermediate between cells and a complete organism 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. In Vertebrates the central nervous system ( CNS) is the part of the Nervous system which is enclosed in the Meninges. 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). Hemolymph or haemolymph is the Blood analogue used by all Arthropods and most Mollusks that have an Open circulatory system. A similar diffusion effect also occurs in some insect caterpillars. In these groups the respiration is more reminiscent of lungs. lung is the essential Respiration organ in air-breathing Animals including most Tetrapods a few Fish and a few Snails The most primitive In spiders and other arachnids they have structures called book lungs. A book lung is a type of Respiration organ used for atmospheric gas exchange and is found in Arachnids such as Scorpions and Spiders Each of these

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