Along the sides of the vestibule are turbinates; mucous membrane covered projections that contain a very rich blood supply from the internal and external carotid arteries. They warm and humidify the inspired air.

The epiglottis is a leaf shaped structure, immediately posterior to the base of the tongue, above the larynx. When food or liquids are swallowed, the epiglottis closes over the larynx, protecting the lower airways from aspiration.

Vesicular breath sounds are heard throughout the chest and are best heard at the base of the lungs. They are low pitched soft sounds, best heard during inspiration.

Stridor is the name given to high pitched sounds produced when air passes through a partially obstructed or narrowed upper airway on inspiration. Stridor is associated with respiratory distress and can be life-threatening, because the airway is compromised.

Asthma is a disorder of the bronchial airways characterized by periods of reversible bronchospasm (spasms of prolonged contraction of the airway). Asthma is often called, the reactive airway disease. This complex disorder involves biochemical, immunologic, endocrine, infectious, autonomic, and psychological factors.

The trachea or windpipe, is a tube that connects the pharynx and larynx to the lungs, allowing the passage of air. The trachea begins immediately below the larynx (voice box) and runs down the center of the front part of the neck and ends behind the upper part of the sternum. Here, it divides to form two branches that enter the lung cavities. The trachea is made up of fibrous and elastic tissues and smooth muscle.

The largest and most efficient muscle is the diaphragm. The diaphragm is a large muscle that lies under the lungs and separates them from the organs below. As the diaphragm moves down or flattens, the ribs flare outward, the lungs expand and air is drawn in. This process is called inhalation or inspiration. It is attached to the spine, ribs and sternum and is the main muscle for respiration, playing a very important role in the breathing process.

Byssinosis is a rare lung disease caused by breathing cotton dust or dusts from other vegetable fibers such as flax, hemp, or sisal. It is sometimes referred to as brown lung disease. It is a form of occupational asthma. Symptoms of byssinosis are: tightness in the chest, wheezing and coughing, which are similar to asthma.

Hemoptysis is the expectoration (coughing up) of blood or of blood-stained sputum from the bronchi, larynx, trachea, or lungs (e.g., in tuberculosis or other respiratory infections or cardiovascular pathologies).

A condition in which an extreme decrease in the concentration of oxygen in the body accompanied by an increase in the concentration of carbon dioxide leads to loss of consciousness or death. Asphyxia can be induced by choking, drowning, electric shock, injury, or the inhalation of toxic gases.

Expiratory reserve volume is the maximal amount of gas that can be exhaled from the resting end-expiratory level. In a deep and forceful expiration, the lungs are capable of exhaling a volume which is in excess to the tidal volume and the inspiratory reserve volume. This is known as the expiratory reserve volume (ERV). In a healthy young adult ERV is approximately 1.3 – 1.5 litres.

Hyperpnoea is the term used to indicate over breathing or hyperventilation. It is an abnormal increase in the rate and depth of breathing.

Funnel chest is a deformity in which the sternum is depressed and the organs that lie below it are compressed. In severe cases, sternum may actually touch the spinal column.

Resonant sounds are low pitched, hollow sounds heard over normal lung tissue.

Capnography is a noninvasive procedure. It is used to measure exhaled carbon dioxide concentrations of client receiving mechanical ventilation. Capnography requires continuous sampling of exhaled air. The test is noninvasive and painless. Client who require capnography already have an endotracheal tube or tracheostomy tube in place for mechanical ventilation or airway management. A sensor is attached to the endotracheal tube or tracheostomy tube to measure end tidal carbon dioxide.