Glossary of Respiratory Terms

While discussing breathing and other lung problems with your doctor you may encounter some of the following terms. You may follow the links for more detailed information on some of the words. You can also find more respiratory information in "Respiratory System."

Acinus: The berrylike ending of a tiny airway in the lung, where the alveoli (air sacs) are located.

Acute: Severe or with sudden onset and short timespan.

Airways: Tubes that carry air into and out of the lungs.

Alveoli: Tiny sac-like air spaces in the lung where carbon dioxide and oxygen are exchanged.

Antibiotic: A drug that kills or inhibits the growth of bacteria. (Read about "Microorganisms" "Antibiotics")

Antibodies: Specific proteins produced by the body's immune system that bind with foreign proteins (antigens). (Read about "The Immune System")

Artery: A blood vessel that carries blood from the heart to the rest of the body. (Read about "Vascular System")

Asthma: Respiratory condition caused by narrowing of the airways; symptoms include recurrent attacks of wheezing, coughing, shortness of breath, and labored breathing. (Read about "Asthma")

Bronchiole: The smaller airways of the lungs.

Bronchiolitis: Inflammation of the bronchioles, usually caused by a viral infection. (Read about "Bronchiolitis")

Bronchodilator: A drug that relaxes the smooth muscles of the airways and relieves constriction of the bronchi.

Bronchopulmonary: Pertaining to the lungs and air passages.

Bronchopulmonary dysplasia (BPD): A chronic lung disease of babies, which develops most commonly in the first 4 weeks after birth. (Read about "Bronchopulmonary Dysplasia")

Capillaries: The tiniest blood vessels; capillary networks connect the arterioles (the smallest arteries) and the venules (the smallest veins). (Read about "Vascular System")

Cell: Basic subunit of every living organism; the simplest unit that can exist as an independent living system.

Chronic: Of long duration; frequently recurring.

Cor pulmonale: Heart disease that results from resistance to the passage of blood through the lungs and pulmonary hypertension (Read about "Pulmonary Hypertension"); it often leads to right heart failure. (Read about "Congestive Heart Failure")

Corticosteroids: Drugs that mimic the action of a group of hormones produced by adrenal glands; they are anti-inflammatory and act as bronchodilators.

Cyanosis: Bluish color of the skin due to insufficient oxygen in the blood.

Cystic fibrosis: A serious genetic disease of excretory glands, affecting lungs and other organs; it causes production of very thick mucus that interferes with normal digestion and breathing. (Read about "Cystic Fibrosis" "Genetics")

Diuretic: A drug that promotes the excretion of salt and water by the kidney.

Duct: A passage or tube with well-defined walls for the passage of air or liquids.

Dysplasia: Abnormal development or growth.

Edema: Abnormal accumulation of fluid in body tissues.

Emphysema: Chronic lung disease in which there is permanent destruction of alveoli. (Read about Emphysema in "Chronic Obstructive Pulmonary Disease")

Gas exchange: Primary function of the lungs; transfer of oxygen from inhaled air into the blood and of carbon dioxide from the blood into the lungs.

Genetic: Inherited through genes passed on by one or both parents. (Read about "Genetics")

Hyaline membrane disease: A respiratory disease of newborns, especially premature infants, in which a membrane composed of proteins and dead cells forms and lines the alveoli making gas exchange difficult or impossible. (Read about "Preterm Labor")

Hypertension: High blood pressure. (Read about "Hypertension: High Blood Pressure")

Immunization: Protection from disease by administering vaccines that induce the body to form antibodies against infectious agents. (Read about "Immunizations")

Inflammation: Response of the body tissues to injury; typical signs are swelling, redness, and pain.

Mechanical ventilation: Use of a machine called a ventilator or respirator to improve the exchange of air between the lungs and the atmosphere.

Membrane: Thin, flexible film of proteins and lipids that encloses the contents of a cell; it controls the substances that go into and come out of the cell. Also, a thin layer of tissue that covers the surface or lines the cavity of an organ.

Mucus: A thick fluid produced by the lining of some organs of the body.

Oxygen: Colorless odorless gas that makes up about 20 percent of the air we breathe; it is essential to life because it is used for the chemical reactions that occur in the cells of the body.

Patent ductus arteriosus: Abnormal persistence of the opening in the arterial duct that connects the pulmonary artery to the descending aorta; this opening normally closes within 24 hours of birth. (Read about patent ductus arteriosus in "Congenital Heart Defects")

Pathogenesis: The cellular events and reactions that occur in the development of disease.

Pathophysiology: Altered functions in an individual or an organ due to disease.

Pleurisy: An inflammation of the pleura, the lining of the lungs and chest cavity. (Read about "Pleurisy")

Pneumonia: Inflammation of the lungs. (Read about "Pneumonia")

Pneumothorax: Accumulation of air or gas in the space between the lung and chest wall, resulting in partial or complete collapse of the lung. (Read about "Pneumothorax")

Positive pressure ventilation: Provision of oxygen under pressure by a mechanical respirator.

Progressive: Increasing in severity.

Pulmonary: Pertaining to the lungs.

Pulmonary hypertension: Abnormally high blood pressure in the arteries of the lungs. (Read about "Pulmonary Hypertension")

Respiration: Process of exchanging oxygen from the air for carbon dioxide from the body; includes the mechanical process of breathing, gas exchange, and oxygen and carbon dioxide transport to and from the cells.

Respiratory distress syndrome: A lung disease that occurs primarily in premature infants; the newborn must struggle for each breath and the skin turns blue, reflecting the baby's inability to get enough oxygen. It can also affect adults. (Read about "Respiratory Distress Syndrome in Infants" "Preterm Labor")

Respiratory failure: Inability of the lungs to conduct gas exchange.

Risk factors: Habits, traits, or conditions in a person or in the environment that are associated with an increased chance (risk) of disease.

Surfactant: Fluid secreted by the cells of the alveoli that reduces the surface tension of pulmonary fluids; it contributes to the elastic properties of pulmonary tissue.

Symptom: Any indication of disease noticed or felt by a patient; in contrast, a sign of an illness is an objective observation.

Symptomatic treatment: Therapy that eases symptoms without addressing the cause of disease.

Ventilation: Exchange of air between the lungs and the atmosphere so that oxygen can be exchanged for carbon dioxide at the alveoli.

Ventilator: A breathing machine that is used to treat respiratory failure by promoting ventilation; also called a respirator.

Wheezing: Breathing with a rasp or whistling sound; a sign of airway constriction or obstruction.

Related Information:

    Respiratory System

    The Common Cold

    Influenza