Respiration

A frog respires by two different methods, one in water and one on land.

In water the skin alone serves for respiration: oxygen dissolved in the water diffuses in across the moist skin. This is cutaneous respiration.

On land the buccal cavity, the skin and the lungs all act as respiratory organs. Breathing through the lungs is pulmonary respiration.

The lungs are a pair of elongated, pink, sac-like structures in the upper part of the trunk (the thorax).

Air is drawn in through the nostrils, passes into the buccal cavity and from there to the lungs.

During aestivation and hibernation, gas exchange takes place through the skin.