The bottom of each lung.

The protective bones and cartilage that surround the respiratory organs; includes the sternum and thoracic cage.

Subdivisions of the trachea that convey air to and from the lungs; also known as bronchial tubes.

Very tiny airway branches that split off of the bronchi.

The ridge that separates the openings of the right and left main bronchi at their junction with the trachea.

A dome-shaped structure between the thoracic and abdominal cavities, which contracts to increase thoracic volume and inflates the lungs.

A leaf-like structure of fibrocartilage that closes the opening to the larynx when you swallow food and liquid, and which opens to allow air into the larynx when you breathe.

The paranasal sinus located in the ethmoid bone.

The bony and cartilaginous tubes that connect the middle ear with the nasopharynx, and which equalize pressure on both sides of the tympanic membrane.

The process of breathing out.

A process that involves the exchange of oxygen and carbon dioxide between the atmosphere and the cells of the body.

The paranasal sinus located in the frontal bone.

The space between the vocal cords.

The process of breathing in.

A process that involves gas exchange at the cellular and tissue levels.

The third section of the pharynx, through which air, food, and liquids pass.

The organ of voice production; also known as the voice box.

Division of the trachea that extends into the left lung.

Tonsils that are located at the base of the tongue.

The main organs of the respiratory system.

The paranasal sinus located in the maxillary bone.

A cavity that divides the lungs and which contains the trachea, esophagus, heart, superior and inferior vena cavae, and aorta.

An area of the brain that acts as a control center that initiates and sustains the breathing process.

A cavity on either side of the nasal septum that filters, warms, and humidifies inhaled air.

The first section of the pharynx, through which air passes.

The beginning of the upper respiratory tract; composed of cartilage and bone.

The area located on the roof of the nasal cavity, which is connected to the senses of smell and taste.

The second section of the pharynx, through which air, food, and liquids pass.

Tonsils that are located on either side of the throat.

Two air-filled cavities in the bones of the face that are lined by mucous membranes; include the frontal, ethmoid, maxillary, and sphenoid sinuses.

The membrane that lines the thoracic cavity and upper side of the diaphragm.

Tonsils that are located in the upper part of the throat behind the nose; also known as adenoids.

The muscular, tubular passage of the digestive and respiratory tracts that extends from the back of the nasal cavity and mouth to the esophagus; also known as the throat.

The space between the parietal and visceral layers of the pleura.

The fluid located between the parietal and visceral layers of the pleura, which helps reduce

The process of gas exchange.

The number of breaths that a person takes in a minute; a type of vital sign used to measure the function of the respiratory system.

The area that is responsible for warming and humidifying the air that travels through it.

Division of the trachea that extends into the right lung.

The partition that divides the nasal cavities into right and left sides.

The paranasal sinus located in the sphenoid bone.

The breastbone.

The rib cage.

The air tube that extends from the larynx into the thorax and which allows air to travel to and from the lungs.

The area that is responsible for the inhalation and humidification of air and for transporting air to the lower respiratory tract.

The process by which air moves into and out of the lungs.

The area that contains coarse hairs that act as a first line of defense against infection.

Temporary interruption of breathing.

Drawing in of a foreign body, food, or fluid through the nose, throat, or lungs during inspiration.

Condition characterized by sudden, periodic attacks of dyspnea accompanied by wheezing; caused by a spasm of the bronchial tubes or by swelling of the mucous membranes of the bronchi.

Collapsed or airless lung caused by any condition.

Condition of slower-than-normal breathing.

Inflammation of the mucous membranes of the bronchial tubes.

A malignant tumor that originates in the bronchi; also known as lung cancer.

Sudden, involuntary contractions in the bronchi.

Unusual breathing pattern characterized by periods of apnea, followed by gradually increasing respirations.

Disease characterized by a reduced ability of the lungs to perform their function of ventilation.

Acute (short-term) inflammation of the respiratory mucous membranes; also called nasopharyngitis.

Childhood disease characterized by a “barking” cough and high-pitched breathing.

Condition of bluish tint to the skin due to lack of oxygen circulation to the body tissues.

Inherited disease that affects the respiratory system, pancreas, and sweat glands.

Difficult or painful breathing.

Serious infection of the nose and throat in which a thick sheet of gray matter covers the pharynx, obstructing the flow of air.

Chronic pulmonary disease characterized by an abnormal increase in the size of the alveoli accompanied by loss of elasticity; results in shortness of breath and impaired heart function.

Pus in the pleural cavity; usually the result of a lung infection.

Inflammation of the epiglottis.

Condition of normal breathing.