Structures of the Respiratory System

What is the function of the respiratory system?

For organisms, rather than single cells, respiration means the process of gas exchange between a body and the environment. The human respiratory system picks up oxygen from the air we inhale and releases carbon dioxide into the air we exhale. With each breath, air enters the body through the air passageways and fills the lungs, where gas exchange takes place. The circulatory system links this exchange of gases in the lungs with our body tissues. The respiratory system consists of the nose, pharynx, larynx, trachea, bronchi, and lungs.

Nose The respiratory passageways transport air into some of the most delicate tissues in the body. To keep lung tissue healthy, air entering the respiratory system must be filtered, moistened, and warmed. Hairs lining the entrance to the nasal cavity start the filtering process by trapping large particles. Incoming air is warmed in the inner nasal cavity and sinuses. These areas produce mucus that moistens the air and catches even more dust particles. If you've ever blown your nose after spending time in a dusty environment, you've seen evidence of the way nasal hairs and mucus protect the lungs.

In Your Notebook In your own words, compare and contrast cellular respiration and respiration at the organism level.