In terms of pressure gradients, what is the difference between how frogs fill their lungs and how lizards fill their lungs?

Question

What will be an ideal response?

Answer 1

Answer: An amphibian ventilates its lungs using a buccal force pump. In the first phase of ventilation, the frog expands its buccal cavity and draws air in through its open nares. Then, the glottis, which was closed, opens to allow the lungs to expel spent air into the buccal cavity and out the mouth and nares. The nares and mouth then close, the floor of the buccal cavity rises, and the fresh air in the buccal cavity is PUSHED into the lungs because the pressure in the buccal cavity is greater than the pressure in the lungs. The glottis then closes, which seals off the lungs and prevents air escape. This allows time for gas exchange. Lizards increase the volume of the chest cavity so that air is SUCKED into the lungs. During inspiration, the volume of the chest cavity increases through the contraction of intercostal muscles (snakes and lizards), sheetlike abdominal muscles (turtles and tortoises), or diaphragmaticus muscles (crocodilians). The increase in chest volume decreases lung pressure, which causes air to enter the lungs. During expiration, the volume of the chest cavity decreases, increasing the pressure and causing air to exit.