| A | B | 
| upper respiratory tract | nose, pharynx, larynx | 
| lower respiratory tract | trachea, bronchi, bronchioles, alveoli | 
| functions of the nose | air is filtered, warmed, and humidified | 
| nostrils | openings in nose through which air enters | 
| nasal cavity | portion of nose that warms and humidifies air, and provides sense of smell | 
| sinuses | open spaces around nasal cavity that produce mucus and lighten the skull | 
| lacrimal sacs | collect tears from lacrimal glands; drain into nasal cavity | 
| conchae | mucus-covered structured that protrude into nasal cavity, helping to humidify air | 
| pharynx | passageway for air and food | 
| nasopharynx | area of pharynx behind nasal cavity | 
| oropharynx | area of pharynx behind mouth | 
| laryngopharynx | area of pharynx behind larynx | 
| larynx | "voicebox" - produces sound | 
| cartilage pieces | exterior of larynx - makes up "Adam's apple" | 
| vocal cords | 2 bands of tissue in the larynx which vibrate to produce sound | 
| glottis | space between the vocal cords, opens into trachea | 
| epiglottis | flap of cartilage that covers trachea during swallowing | 
| trachea | "windpipe" that brings air to lungs | 
| bronchi | left and right branches of the trachea | 
| secondary bronchi | smaller tubes that branch off the bronchi | 
| bronchioles | very small tubes that branch off secondary bronchi | 
| alveoli | air sacs at the ends of secondary bronchi | 
| function of alveoli | gas exchange | 
| spongy tissue of lungs | composed of clusters of alveoli | 
| right lung | consists of three lobes | 
| left lung | consists of two lobes | 
| pleura | lining covering lungs and inner surface of thoracic cavity | 
| respiratory mucosa | mucos membrane lining inside of respiratory tract | 
| pulmonary ventilation | breathing - bringing air into lungs | 
| external respiration | exchange of gases between lungs and bloodstream | 
| internal respiration | exchange of gases between bloodstream and body cells | 
| inspiration | inhaling air into lungs | 
| expiration | exhaling air from lungs | 
| inspiratory muscles | diaphragm and external intercostals | 
| expiratory muscles | abdominal muscles and internal intercostals | 
| spirometer | instrument used to measure volumes of air in ventilation | 
| tidal volume | amount of air exchanged during a normal breath | 
| inspiratory reserve volume | amount of air that can be forcibly inspired after normal breath | 
| expiratory reserve volume | amount of air that can be forcibly exhaled after normal breath | 
| vital capacity | maximum amount of air that can be inhaled or exhaled | 
| residual volume | amount of air remaining in lungs after forceful expiration | 
| total lung capacity | total amount of air that lungs can hold |