Respiratory System of Turtles

Anatomy

• A turtle's respiratory system extends from the mouth to the lungs. The mouth takes in oxygen, which proceeds past the pharynx and through the glottis. The glottis -- a small opening just past the pharynx -- acts as a barrier between it and the larynx and prevents seawater from progressing down into the lungs. After the glottis comes the trachea, which leads to the bronchus, which divides into two bronchial tubes attached to the lungs. Turtles' lungs are above all the other vital organs just beneath the shell.

Breathing

• The mouth draws in oxygen, which passes through the system to the lungs. The turtle's other organs press against the lungs when breathing -- acting like a bellows -- and expel carbon dioxide back through the respiratory system. The lungs can be inflated and have oxygen stored for buoyancy or long periods underwater.

Lungs

• As air enters the spongy pink lungs, the bronchial tubes break into smaller tubes called bronchioles. They, in turn, become smaller until they end at the alveoli or small air sacs where the exchange of gases occurs. Oxygen absorbs into the blood and carbon dioxide expels.

Adaptations

• In emergencies, sea turtles can breathe through the cloaca, a small cavity inside the turtle's head. Leatherback turtles can adjust their breathing rate to recover faster after periods underwater. Leatherbacks and loggerhead turtles have higher levels of hemoglobin and myoglobin that enable them to deliver oxygen more quickly throughout their respiratory system.