This toad has three ways it is able to exchange oxygen and carbon dioxide. First, a toad can breathe through its skin. The toad’s skin captures oxygen with capillaries just beneath the surface. The capillaries then transport the oxygen throughout the body. Blood cells without oxygen pick up carbon dioxide and carry it back to the skin where it diffuses out. The entire process is called cutaneous gas exchange.

      A toad can also breath through its nostrils and down into the lungs. However, because they don’t have ribs or a diaphragm, there isn’t any decrease in pressure to allow air to flow in. Instead, toad lowers the floor of its mouth, causing the throat to expand. The nostrils then open allowing air to enter the wide mouth. The nostrils then close and the toad closes its mouth, forcing the air into the lungs. To get rid of carbon dioxide, when the mouth moves floor of the mouth moves down, it draws air away from the lungs. The nostrils open and the floor of the mouth moves up, thereby pushing the air out of the mouth.

     Finally, toads have a surface on the lining of their mouth which allows gas exchange to take place. This works very similarly to how gas is exchanged throughout the skin.