 Gas exchange: CO 2 out and O 2 in  Control of blood pH  Sound/voice production  Olfaction  Protection for invading organisms

 The nose consists of the external nose and the internal nasal cavity  The nostrils are called the nares.

 Mucus traps microbes and debris  Cilia sweep the mucus to the esophagus to be digested  Air is also moistened and warmed

 Common passageway for the digestive and respiratory systems  Contains the tonsils which help the body fight infection

 Site of the vocal cords  Laryngitis – inflammation of the vocal cords  The epiglottis ensures food is sent to the correct passageway by opening or closing.

 Long tube of smooth muscle and connective tissue  Cartilage rings provide protection and prevent collapse

 Two main branches that lead to each lung  Very sensitive to stimulation so tiny changes may trigger strong cough reflexes

The lungs are found within the pleural cavity that is inside the thoracic cavity.

A few mL of pleural fluid is always present in the pleural space. It is needed for the lungs to properly function. Too much fluid build up is called effusion.

 You have a left and a right lung  The functional units of the lungs where gas exchange happens are the alveoli. CO 2 and O 2 are exchanged by diffusion