Читать книгу Blackwell's Five-Minute Veterinary Consult: Reptile and Amphibian - Javier G. Nevarez - Страница 53

Amphibians have unique adaptations for respiration. In addition to traditional lung (pulmonic) respiration, they can also exchange gas via buccopharyngeal respiration, which allows exchange at the level of the oral and pharyngeal cavity. Cutaneous respiration may comprise up to 80% of the gas exchange, especially in aquatic species. Lateral folds, costal grooves, or cutaneous hairs may be present to increase surface area of the skin and improve the efficiency of cutaneous respiration. Finally, branchial/gill respiration occurs in juvenile stages and in neotenic species.

Amphibians have short tracheas with complete rings and single chambered lungs without alveoli. Instead there are a series of infoldings of the lungs that increase surface area. Lungs are absent in Plethodontidae and reduced or absent in the Hynobiidae.

Anuran larvae have small, simple gills covered by an operculum similar to fish. In contrast, salamander larvae have external gills without an operculum. The gills of caecilians are resorbed before birth/hatch. In anurans, they are resorbed during stages of metamorphosis. Salamanders resorb their gills during metamorphosis but they are retained in neotenic species.