Glossary of Terms

There are many clinical terms associated with pulmonary complications and airway clearance. To communicate more effectively with your physician or healthcare team, we recommend that you review the following commonly used terms.

adhesiveness
Tendency to stick to another substance. The adhesiveness of mucus refers to its tendency to stick to the bronchial wall, making it hard to move.
aerobic capacity
Aerobic exercise is any activity that requires additional effort by the heart and lungs to meet increased demand on skeletal muscles for oxygen. Aerobic capacity is a measure of the extent of an individual's ability to perform aerobic exercise.
alveolar duct
The opening through which air passes between the respiratory bronchioles and the alveoli.
alveoli (singular - alveolus)
The alveolus is a thin-walled sac, at the very end of the airway, where gas exchange takes place.
amyotrophic lateral sclerosis
ALS (also known as Lou Gehrig's disease in the United States and Motor Neuron Disease and Charcot's disease in Europe) is a progressive disease that affects nerve cells found in the brain and spinal cord.
artificial airway
A broad term referring to any plastic, metal or rubber device that can be inserted into the respiratory tract to promote breathing.
aspiration/aspiration pneumonia
The accidental inhalation of saliva, stomach contents, or foreign bodies into the lungs. Aspiration can result in serious, sometimes fatal pneumonia.
atelectasis
An abnormal condition marked by collapse of lung tissue. This prevents the exchange of oxygen and carbon dioxide by the blood.
atelectatic
A condition of airlessness or collapse of all or part of the lung.
atrophy
A wasting or loss of size of a part of the body as a result of disease or other influences.
bacteria (singular-bacterium)
One-celled microorganisms, some of which cause infection. The nature, severity and outcome of any infection caused by a bacterium depends on the species of the bacterium.
bacterial colonization
Bacteria grow and multiply quickly; in just 24 hours one bacterium can become billions. When bacteria overwhelm a part of the body, this is known as bacterial colonization. Bacterial colonization can result in serious illness.
bellows function
The ability of the lungs to expand and contract to permit the intake of oxygen and expulsion of carbon dioxide.
beta-adrenergic agonists
Medications that prevent constriction of smooth muscle in the airways.
bland aerosols
Aerosolized water or saline (salt water) solutions that change the thickness and stickiness of mucus, sometimes making it easier to clear.
bronchi
Large, central airways branching from the trachea.
bronchial hygiene
Care that is given to patients with respiratory disorders to prevent obstruction of the airways by excessive secretions. Bronchial hygiene therapy may include Airway Clearance Therapy, stimulation of coughing, and suctioning. Also called pulmonary hygiene, bronchial toilet, or pulmonary toilet.
bronchial tree
The configuration of the airways, including the bronchi and the bronchioles. The bronchi branch from the trachea, and the bronchioles branch from the bronchi. All of these airways provide a vast area through which the oxygen can enter the blood, an area which measures nearly 35 times greater than the entire surface area of your skin.
bronchiectasis
Bronchiectasis is a disorder of the large bronchi characterized by airway dilation; it is caused by recurrent, destructive inflammation or infection of the airways.
bronchioles
One of approximately six sets of increasingly smaller airways branching from the bronchi.
bronchoconstriction
Constriction of airways that makes breathing difficult. Especially dangerous in combination with mucus plugging.
bronchodilation
Widening of the airways, a result of relaxation of the smooth muscle.
bronchopulmonary
Third-generation airways that branch from the lobar bronchi.
bronchospasm
Sudden constriction of the airways, or bronchoconstriction.
bulbar muscles
The term "bulbar" (bulb-shaped) refers to the area of the brain that controls swallowing and the muscles associated with the swallowing function. Damage to, or weakness in this area may result in the unintentional retention and aspiration of oral secretions.
cholinergic agonists (anticholinergic agents)
A group of drugs that prevent bronchospasm and help reduce mucus production.
cilia
Small, hair-like projections on the outer layer of some cells, including many of those in the bronchial epithelium.
cilia beat
The constant wave motion of cilia that move mucus and trapped particles from the lungs.
ciliated cells
Cells possessing cilia.
clavicle
A long, curved, horizontal bone just above the first rib and forming the front portion of the shoulder sometimes called the collarbone.
congestion
The state of being too full of some substance. Pulmonary complications are likely to result when the lungs are congested with mucus.
corticosteroids
A group of drugs that help prevent bronchoconstriction.
cough
A sudden, forceful expulsion of air from the lungs; an essential protective response that serves to protect the lungs and airways from irritants and secretions and to prevent aspiration of foreign material into the lungs.
cystic fibrosis (CF)
A genetic disease characterized by extremely thick bodily secretions in the digestive and pulmonary systems. Sticky, tenacious secretions in the lungs lead to frequent, debilitating infections, subsequent irreversible lung damage, and eventual early death due to respiratory failure. Conscientious bronchial hygiene is essential in the treatment of CF.
diaphragm
A dome-shaped muscle that separates the chest cavity from the abdominal cavity. The diaphragm aids breathing by moving up and down. When breathing in, it moves down, increasing the space in the chest. When breathing out, it relaxes, decreasing the space in the chest.
dichotomously
"Into two." Airways generally branch "dichotomously" or into two new airways.
DNA (deoxyribonucleic acid)
A large molecule that carries genetic information.
dyskinetic
Impaired ability to move. Dyskinetic cilia results in secretion retention, which may result in pulmonary complications.
dysphagia
Difficulty in swallowing food or liquids, as a result of weakness or abnormality
dyspnea
Shortness of breath or difficulty in breathing.
elasticity
The property of a substance to recover its former shape after being stretched or having some other pressure put upon it.
endocrines
Glandular secretions, including hormones.
epithelial
Having to do with the covering of the organs of the body.
epithelial cells
Cells arranged in one or more layers that line or cover body surfaces and that secrete essential fluids. Both skin and bronchial airways are covered with such cells.
epithelium
The covering of the organs of the body.
esophageal sphincter
A circular band of muscle fibers that close off the opening of the esophagus where it enters the stomach. The esophageal sphincter prevents the flow of partially digested material back into the esophagus.
esophagus
A muscular canal extending from under the tongue to the stomach, the tube through which food passes into the stomach.
exacerbates (-ed)
Furthers, makes worse.
exacerbation(s)
A flare-up or worsening of a condition.
expectoration (-ed, expectorating)
Removing mucus, sputum, or fluids from the throat or lungs by coughing or spitting.
expiratory capacity
The maximum amount of air that can be exhaled after breathing in normally.
expiratory reserve volume
The largest amount of air that can be forced out of the lungs after a normal breath has already been breathed out.
fibroblasts
An undifferentiated cell in the connective tissue that can migrate to the site of an injury and undergo alterations necessary to repair certain types of tissues.
forced expiratory technique (FET)
A strong expiration made by contracting the abdominal muscles while keeping the mouth and glottis open (unlike a cough, which requires closure of the glottis), also called huff technique.
forced expiratory volume in one second (FEV1)
The amount of air that can be forced out in one second after taking a deep breath.
forced expired vital capacity (FEVC, FVC)
The largest volume of air that can be forced out rapidly after taking a deep breath.
functional residual capacity
The amount of air still left in the lungs after breathing out normally.
gas exchange
The process by which oxygen and carbon dioxide are exchanged between the lungs and the bloodstream.
gas-liquid interaction
As it pertains to the airways, the interaction between turbulent airflow and the viscosity of mucus. At a certain flow rate, the movement of air will cause mucus to separate from the epithelium.
gastroesophageal reflux
Gastroesophageal reflux occurs when a defective lower esophageal sphincter allows stomach contents to surge into the esophagus.
generation
Each time an airway branches (usually into two), it gives rise to a new generation of airway. The trachea is generation 0, the stem bronchi the first generation, the lobar bronchi the second generation, etc. Most lungs contain 23 generations of airways.
glottis
A slit-like opening between the vocal cords. The glottis must be closed off to generate an effective cough.
homeostasis
A relative constancy in the internal environment of the body. In healthy individuals, homeostasis is maintained by adaptive responses that control, for example, temperature, hormone secretions, and rates of cell growth.
huff technique (huffing)
A strong expiration made by contracting the abdominal muscles while keeping the mouth and glottis open (unlike a cough, which requires closure of the glottis). Also called forced expiratory technique (FET).
hypersecretion (hypersecretory)
The production of excessive amounts of mucus. Hypersecretion occurs during infections in an attempt to rid the body of the microorganisms causing the infection.
hypoxemia
An abnormal decrease of oxygen in arterial blood.
immunological responses
The body's defenses against infection.
immunosuppressive therapy
The giving of medications that reduce the ability of the immune system to respond to stimulation by substances foreign to the body. Immunosuppressive therapy is used deliberately to prevent rejection of transplanted tissue.
impaired airway clearance
Inability of airway clearance mechanisms (mucociliary clearance (MCC) system and cough) to clear airway mucus effectively.
impaired gas exchange
The mucus occlusion of airways or collapse of alveoli that prevents the transfer of oxygen and carbon dioxide in and out of the bloodstream through normal breathing.
inspiratory capacity
The maximum amount of air that can be inhaled into the lungs from the normal resting position after breathing out normally.
inspiratory reserve volume
The maximum additional amount of air that can be breathed in after breathing in normally.
intercostal muscles
The muscles between the ribs. These muscles are important to deep breathing.
intrapleural pressure
Pressure preceding a cough that is created in the space between the pleural tissue lining the lungs or the thoracic cavity and the lungs themselves.
intubation
Passing a tube into the nose, mouth or trachea to provide an airway for anesthetic gas or oxygen.
larynx
Part of the airway leading from the pharynx (throat) to the trachea. The larynx, lined with mucus membrane and composed of rings of cartilage, forms the bottom portion of the front wall of the throat, sometimes called the voice box.
lobar bronchus
The bronchi stemming directly from the left or right stem bronchus and leading into the lobes of the lung.
lung capacities
Lung volumes that consist of two or more of the primary lung volumes. See total lung capacity, vital capacity, inspiratory capacity, expiratory capacity, and functional residual capacity.
lung volumes
The amounts of air contained by the lungs during various parts of the respiratory cycle; see tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume. See also lung capacities.
lymph
A thin, slightly yellowish, translucent fluid originating in many organs and tissues of the body. Lymph composition is varied depending on the area of the body but generally contains about 95% water, a few red blood cells, and a number of white blood cells; it contains less protein than blood plasma. Lymph circulates in the lymphatic system.
lymphatic system
A network of vessels, valves, ducts, nodes and organs that help to regulate the fluid environment of the body by producing, filtering and conveying lymph and by producing various blood cells. Lymph capillaries and vessels transport fats, proteins and other substances to the blood system and restore fluid that leaks out of the capillaries and cells during normal metabolism. Lymph is moved through the lymphatic system by various body movements (muscle contractions, lung pressure changes, the working of organs).
lymphatics
Pertaining to the lymphatic system of the body.
methylxanthines
A group of drugs that relax smooth muscle in the airways, bronchodilator.
mucociliary clearance
The process by which the coordinated beating of cilia moves mucus up and out of the airways.
mucolytic agents
A group of drugs that thin secretions, making them easier to clear.
mucus
The sticky, slippery material released by mucous membranes and glands. In the lungs, mucus serves as a defense mechanism, trapping bacteria and foreign particles so that they can be moved out of the lungs.
mucus plugging
The collection of mucus plugs. Pulmonary mucus plugging, especially in combination with inflammation, can effectively obstruct the airway, resulting in impaired gas exchange and atelectasis.
mucus plugs
A thick collection of mucus in any part of the body, most often in the airways.
mucus shearing
Sudden separation of mucus from the bronchial wall as a result of rapid, forceful outward airflow such as that which occurs during a cough.
muscular dystrophies
A group of inherited, neuromuscular disorders classified on the basis of specific genetic characteristics. Duchenne muscular dystrophy (DMD) is the most common and most debilitating. Other, less severe forms of muscular dystrophy, including Becker muscular dystrophy (BMD), Emery-Dreifuss muscular dystrophy (EDMD), facioscapulohumeral muscular dystrophy (FMD), limb-girdle muscular dystrophy (LGMD) and myotonic dystrophy MMD), are distinguished from DMD in several ways.
nasal cavity
An opening leading from the face through the nose and into the pharynx, or throat.
necrotizing pneumonia
A lung infection characterized by multiple abscesses and permanent destruction of lung tissue.
obstructive lung disease
A group of respiratory illnesses characterized by decreased airway size and increased airway secretions.
oropharyngeal
Related to the mouth and throat.
otitis
Inflammation or infection of the ear.
pathogens
Any microorganism that causes disease.
percussion
In chest physiotherapy, a technique that includes clapping and vibrating the chest wall with one's hands.
phagocyte/phagocytosis
The process of ingestion and digestion by phagocytes (special white blood cells) of bacteria, dead tissue, or foreign particles.
pharynx
The throat, a tube-like structure from the base of the skull to the esophagus.
phospholipids
A chemical compound consisting of phosphoric acid, fatty acids, and nitrogen.
phrenic nerve
The nerve that governs movement of the diaphragm during breathing.
physiology
The biological study of the functions, activities, and vital processes performed by a normal living organism. Physiology differs from anatomy in that it emphasizes process over structure.
pleuropulmonary infection
An infection located in the lung, pleura, or thoracic cavity, or in related structures.
positive pressure
The delivery of forced air to the lungs, as in mechanical ventilation or intrapulmonary percussive ventilation (IPV) therapy.
pulmonary functions
Measurements taken to determine lung volumes and lung capacities. See, for example, forced expiratory volume in one second (FEV1) and forced expired vital capacity (FEVC).
recombinant human DNA
DNA molecules that have been broken apart and put back together in different forms.
residual volume
The air that remains in the lungs after breathing out as fully as possible.
respiratory bronchioles
The smallest of the bronchioles, these connect the terminal bronchioles to the alveolar ducts.
respiratory failure
The failure to exchange enough oxygen and carbon dioxide in the lungs.
restrictive lung disease
A respiratory disorder characterized by restriction of expansion of the lungs or chest wall, resulting in fixed or diminished lung volumes and vital capacities.
RhDNase
An enzyme that breaks down DNA strands. Marketed as Pulmozyme® Inhalation Solution.
scalene muscles
Muscles that extend from the last five cervical vertebrae to the first and second ribs. Their function is to raise these two ribs.
serous fluid
Thin, watery liquid that surrounds organs and allows them to move freely.
sinusitis
Inflammation of one or more of the nasal sinuses.
spinal deformity
Abnormal curvature of one or more portions of the spine.
squamous cells
A flat, scaly cell without cilia. Certain kinds of lung damage, including bronchiectasis, result in the replacement of ciliated cells with squamous cells; impaired airway clearance results.
status asthmaticus
An acute, severe, and long-lasting asthma attack. A lack of oxygen in blood, blue skin, and unconsciousness may result.
sternocleidomastoid muscles
Muscles that run from the sternum to the skull on either side of the neck. Contraction of the sternocleidomastoid muscles during inspiration slightly elevates the ends of the ribs, increasing the size of the thoracic cavity. Use of these muscles during normal breathing greatly increases work of breathing.
sternum
A long, flat bone in the center front of the rib cage, sometimes called the breastbone.
suctioning
The mechanical removal of respiratory secretions from the trachea.
terminal bronchioles
The end of the nonrespiratory airway, branching into the respiratory bronchioles.
thoracic cavity
The chest area, including part of the abdominal region.
thorax
The chest area, including part of the abdominal organs.
tidal volume
The amount of air inhaled and exhaled during normal breathing.
total lung capacity (TLC)
The total amount of air in the lungs after a maximum inhalation; the sum of the vital capacity and the residual capacity.
trachea
The tube in the neck, extending from the voicebox to the bronchi, that leads air into the lungs; the windpipe.
tracheostomy
An opening through the neck and into the trachea, through which a tube is inserted to create an airway.
vagus nerve
Either of the longest pair of cranial nerves, governing speech, swallowing, and other functions.
ventilation/perfusion mismatch
An imbalance between air and blood at the interface of gas exchange.
vicious cycle
Recurrent, ever worsening episodes of pulmonary inflammation, infection, mucus hypersecretion, airway obstruction, and lung damage.
viscoelasticity
The tendency of secretions to stick together.
viscosity (viscous)
Thickness of a fluid, tendency of the fluid to be thick, syrupy, and/or sticky.
vital capacity (vital capacities)
The amount of air that can be breathed out after taking the largest possible breath.