Respiratory System

Frogs use two entirely different sets of respiratory organs depending on where they are. In water, gas exchange happens across the skin (cutaneous respiration): dissolved oxygen simply diffuses in through the moist skin surface. On land, three routes operate together - cutaneous respiration continues, buccal (buccopharyngeal) respiration works by keeping the mouth closed while the nostrils stay open and the floor of the buccal cavity is rhythmically raised and lowered to pump air in and out, and pulmonary respiration uses a pair of elongated, pink, sac-like lungs in the upper trunk, reached by air passing in through the nostrils and across the buccal cavity. During aestivation and …