inhaling: diaphragm contracts, rib cage rises and increases the volume of the chest cavity, air rushes into the lungs expiration: diaphragm relaxes & moves up into original dome shape. This decreases the chest volume & moves air out of the lungs diaphragm: a sheet of muscle that separates the organs of the chest cavity from those of the abdminal cavity. Moves up and down to aid in respiration. alveoli: tiny air sacs within the lungs where gas exchange occurs between air & blood. 1 cell thick and located at the end of the bronchioles. lungs: two spongy organs that are large & sac-like in the thoracic cavity enclosed by the diaphragm and rib cage. where external respiration happens pharynx: throat; passageway for food to the esophagus and air to the larynx nasal cavity: the cavity behind the nose and above the roof of the mouth that filters air and moves mucous and inhaled contaminants outward and away form the lungs. bronchioles: small tubes that branch off the bronchi that contain clusters of alveoli at each end. cilia: The fine hairlike projections from certain cells such as those in the respiratory tract that sweep in unison and help to sweep away fluids and particles trachea: The main air tube leading into the respiratory system. The trachea is made of alternating rings of cartilage and connective tissue. epiglottis: a flap of cartilage that prevents food from entering the trachea when eating and opens to allow breathing and speaking bronchi: Has ring of cartilage to keep pathway open, branches off trachea in a Y shape to take air into lungs colds: caused by viruses that mutate regularly- can be very serious for infants, elderly & those with other health complications bronchitis: inflammation & excess mucus production in the bronchi & bronchioles, caused by viral or bacterial infection or by chemical irritants (ex. smoke) - causes narrowing of the air passageways, making breathing & gas exchange difficult, leads to coughing asthma: chronic allergic disorder characterized by episodes of severe breathing difficulty, coughing, and wheezing using the air passage to narrow & causes shortness of breath corticosteroids: drug delivered directly to the lungs by an inhaler, stimulate air passages