Bullfrog (Rana catesbeiana) ventilation: how does the frog breathe?

Two short-term cyclic events, buccal oscillations and ventilatory cycles, occur in the bullfrog's respiration. Dutring ventilation the frog fills the buccal cavity with air, then blows the pulmonary contents through the buccal cavity, and finally closes the nostrils while pumnping the buccal contents into the lungs. The pulmonary efflux streams by the buccal contents with minimal mixing, and relatively pure air is pumped into the lungs. Buccal oscillations serve mainly to flush out the buccal cavity between ventilatory cycles.