Place where air enters the body; warms, moistens, and filters incoming air.

Main organ of the respiratory system.

Smaller branches of the bronchi inside the lungs.

Main muscle that controls breathing by changing pressure in the chest cavity when it contracts or relaxes.

Common passageway of your nasal cavity and your mouth.

Flap that closes over the trachea when swallowing to keep food from “going down the wrong pipe”; remains open when breathing.

Windpipe; tube leading into the chest cavity.

“Grape-like”, Tiny, thin walled sacs where oxygen and carbon dioxide are exchanged.

Branches of the trachea that lead to each lung.

“Voice box”; makes sounds as air passes through vocal cords.

During respiration, Carbon dioxide diffuses from the _______________ to the _____________.

During respiration, oxygen diffuses from the _______________ to the _____________.

When inhaling, the diaphragm muscle contracts causing the volume of the chest cavity to _____________, which causes pressure in the lungs to ________________, and air to move _______. 

When exhaling, the diaphragm muscle relaxes causing the volume of the chest cavity to _____________, which causes pressure in the lungs to ________________, and air to move _______.