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Both the lungs and the skin serve as respiratory organs in amphibians. The ventilation of the lungs in amphibians relies on positive pressure ventilation. Muscles lower the floor of the oral cavity, enlarging it and drawing in air through the nostrils into the oral cavity. With the nostrils and mouth closed, the floor of the oral cavity is then ...
The lungs of most frogs and other amphibians are simple and balloon-like, with gas exchange limited to the outer surface of the lung. This is not very efficient, but amphibians have low metabolic demands and can also quickly dispose of carbon dioxide by diffusion across their skin in water, and supplement their oxygen supply by the same method.
In this spider diagram, the position of the book lungs is labelled 1. Spider book lungs (cross section) Internal anatomy of a female spider, book lungs shown in pink A book lung is a type of respiration organ used for atmospheric gas-exchange that is present in many arachnids, such as scorpions and spiders.
In amphibians, the trachea is normally extremely short, and leads directly into the lungs, without clear primary bronchi. A longer trachea is, however, found in some long-necked salamanders, and in caecilians. While there are irregular cartilagenous nodules on the amphibian trachea, these do not form the rings found in amniotes. [28]
The anatomical structure of the lungs is less complex in reptiles than in mammals, with reptiles lacking the very extensive bronchial tree found in mammalian lungs. Gas exchange in reptiles still occurs in alveoli , but reptiles do not possess a diaphragm , therefore ventilation occurs via a change in the volume of the body cavity which is ...
Diagram showing the general layout of air sacs in a bird. Birds have a system of air sacs in their ventilation system. [2] The air sacs work to produce a unidirectional flow where air enters and exits the lung at the same rate, contrasting the lungs of other tetrapods such as mammals where air enters and exits the lung in a tidal ventilation.
Amphibians breathe by means of buccal pumping, a pump action in which air is first drawn into the buccopharyngeal region through the nostrils. These are then closed and the air is forced into the lungs by contraction of the throat. [34] They supplement this with gas exchange through the skin which needs to be kept moist. [35]
The microscopic structure of a gill presents a large surface area to the external environment. Branchia ( pl. : branchiae) is the zoologists' name for gills (from Ancient Greek βράγχια ). With the exception of some aquatic insects , the filaments and lamellae (folds) contain blood or coelomic fluid , from which gases are exchanged ...