Asthma - Glossary
Allergen
A protein that causes one to have an allergic reaction. Examples include: foods, animal dander, and certain drugs.
Allergy
A type of excessive immune system reaction to a substance in a person's environment.
Alveolus / Alveoli
The millions of tiny compartments, also called "air sacs", within the lungs at the ends of the airways. This is where gas exchange takes place: blood picks up oxygen (from air a person has breathed in) and releases carbon dioxide (to be breathed out).
Angina
A severe and crushing chest pain just behind the breastbone (the sternum) and a feeling of pressure and suffocation. The condition is due to an inadequate supply of oxygen to the heart muscle.
Antibiotic
Medication used to treat infection caused by bacteria. Antibiotics do not protect against viruses and do not prevent the common cold.
Antibodies
Proteins that the body makes to protect itself from foreign substances (antigen). An auto-immune response occures when the immune system mistakes some part of the body as a pathogen and attacks it. Antibodies in people with type 1 diabetes have destroyed their own insulin-making beta cells. Overreaction of the immune system occurs in people with allergic reactions against food or environmental particles.
Antigen
A substance that can trigger an immune response, resulting in the production of an antibody as a part of the body's defense against infection and disease.
Anti-inflamatory medicines
Used to prevent symptoms by keeping airways from swelling when exposed to triggers.
Asthma
A chronic inflammatory disorder in which mast cells, Eosinophils, T lymphocytes (and others) play a role. The inflammation causes recurrent episodes of wheezing, breathlessness, chest tightness, and cough particularly at night and/or in the early morning. These symptoms are usually associated with widespread, but variable, airflow limitation. Asthma is a "disorder" rather than a disease.
Asthma attacks
An asthma attack (episode) often starts with a tightness in the chest. In many cases it is followed by continuous irritation of the throat and eventually acute breathlessness. This can result in a lack of oxygen and anxiety. Exhalation in particular feels difficult and is accompanied by wheezing sounds. An asthma attack can last from a couple of minutes up to several hours. In children, coughing is generally the main symptom for asthma.
Bronchial asthma
Bronchial asthma, commonly referred to as "asthma", is a chronic inflammatory disorder of the respiratory system. During an asthma attack, constriction of the air passages results in shortness of breath. There are differences between allergic asthma and non-allergic asthma. However, in many cases mixed forms occur. In the case of allergic asthma stimulants that trigger allergies (allergens) cause the immune system to have an acute reaction. The compounds produced by the body in the course of this reaction (e.g. histamine) can trigger asthma attacks. Non-allergic asthma is triggered by other factors, e.g. infections (of the respiratory passage), drug intolerance, provocative agents/toxins, physical exertion and stress. Nowadays asthma is the most frequent chronic disease in children in the industrialized countries.
Bronchioles
The tiny (<1mm in diameter) branching airways that lead from the bronchi to the alveoli. They also produce mucus.
Bronchospasm
The tightening of the muscle bands that surround the airways, causing the airways to narrow.
Bronchus / Bronchia
The bronchia or bronchial tubes are the final branched sections of the trachea (windpipe) which initially forks into two 'main stems'. These 'stems' divide many times, into even finer bronchioles, finally ending in the pulmonary alveoli.
Ciliated epithelium
The ciliated epithelium consists of specialized epithelial cells which cover a large area of the air passages. They are lined with small cilia (hair-like structures) which dispose of mucus by making wave-like motions. Thus, any foreign bodies that have entered the airways (e.g. dust particles or pathogens) which are absorbed in the mucus are transported towards the throat, i.e. this is a cleaning mechanism of the air passages.
COPD
Chronic Obstructive Pulmonary Disease: This umbrella term refers to a large number of different pulmonary disorders. Typical symptoms: coughing, sputum, respiratory distress under physical exercise or stress. The two major diseases are chronic-obstructive bronchitis and pulmonary emphysema. The word "obstructive" refers to a constant narrowing of the bronchia, leading to a shortness of breath. In the case of pulmonary emphysema, the alveoli have been damaged or destroyed. The main cause for the development of a COPD is smoking cigarettes ("smoker's lung", "smoker's cough").
Corticosteroids
A type of medication used to reduce inflammation. These drugs mimic a substance produced naturally by the adrenal glands. In asthma, these drugs are often taken through an inhaler for long-term control. They may also be taken orally or given intravenously for a short time if asthma symptoms become out of control.
Dust mites
Tiny insects, unable to be seen without a microscope, that are present in carpet, stuffed animals, upholstered furniture, and bedding including pillows, mattresses, quilts, and other bed covers. Dust mites are one of the most common allergens and, therefore, a common asthma trigger. They grow best in areas with high humidity.
Eosinophil
A type of white blood cell whose major role is to assist in protecting against parasitic infections. It is also associated with the inflammation at the root of asthma. Those with asthma tend to have more eosinophils in their blood and an unusual number of eosinophils migrate into their lungs. It is still not entirely clear whether eosinophils cause some of the problems that asthmatics experience, or whether they are just associated with the process without doing damage themselves.
Helper T cell
These cells activate plasma cells (plasmacytes) and killer cells (K cells).
Histamine
Histamine is a messenger substance produced when the immune system responds. In conjunction with other substances, it is responsible for inflammation and itching (pruritus). Various drugs have been de-signed to reduce or eliminate the effects of histamine (antihistamines). They are therefore used in the treatment of allergies.
Immune system
The body's defense system that is responsible for distinguishing our own body components from everything else that is foreign to us and potentially dangerous. The immune system works to seek and kill invaders like bacteria and viruses, as well as harmful foreign substances.
Killer cells
If a virus has already multiplied in host cells, these cells can be identified and subsequently destroyed by killer cells.
Macrophages
In the course of a primary non-specific defense reaction, the macrophages kill foreign invading particles such as bacteria and viruses. If this defense is inefficient, a more elaborate immune response will occur . Here, the macrophages also play a decisive role: they present the constituents (antigens) of the invading organisms on their surface, thus informing the helper T cells.
Mast cell
A cell type containing chemicals that produce an asthmatic reaction when exposed to an allergen. These cells are in most body tissues, but are also in connective tissue, such as the innermost layer of skin (dermis) and also in the airways.
Micro array technology
Micro array technology is a generic term used for different assay systems in molecular biology whereby a large number of individual tests can be carried out in a small space. DNA microarray technology ("genome chips") makes it possible to determine the RNA quantity of a probe. In this way it can be substantiated whether and to what extent specific genes are active in the cells of a test subject. For this, tiny parts of DNA of a known sequence are applied on certain spots of a substrate (e.g. glass plate). The specimen with the RNA (previously treated and marked with fluorescent substance) is added. In complementary sequences, the sample RNA will bind to the DNA on the chip. Due to the defined position on the substrate, subsequent evidence can be found on the gene activity in the examined organism by measuring the fluorescent signals.
Mucus
A substance secreted by various tissues in the body (mucus membranes), made up of water, mucin, salts, and some cells. In the lungs, mucus serves to lubricate the insides of the airways and to trap foreign particles so that they can be coughed out. In asthma, however, an excess of mucus is produced and can actually block airways. Mucus also tends to be thicker and more viscous in asthmatics.
Obstruction
In medicine, an obstruction is referred to as a blockage or narrowing of vessels or channels, e.g. a construction of the respiratory passages.
Plasmacytes
When activated, these cells produce antibodies. Matching antibodies bind to the antigens of the specific intruder which are subsequently killed by the macrophages. The antibodies also initiate other mechanisms of the immune system. As initially many antibodies produced do not match the antigens, it takes two to three days until the immune response is effective. Plasmacytes also produce memory cells which in the case of a recurring infection of the same pathogen, can immediately produce matching anti-bodies.
Pulmonary alveoli
The final branches of the respiratory tree are made up of small air sacs, called alveoli. They are sur-rounded by a network of tiny capillaries. The oxygen contained in the inhaled air diffuses from the alveoli into the blood whereas the carbon dioxide is transferred from the blood into the alveoli (gas exchange) and will be exhaled.
Pulmonary emphysema
Pulmonary emphysema is an over-inflation of the lung, damaging or even destroying alveoli. In the case of chronic pulmonary emphysema which is often a result of cigarette smoking, the lung is permanently damaged. The tissue looses flexibility and alveoli are irreversibly damaged. In an asthma attack, "acute overinflation" may occur. In many cases, any damaged tissue can regenerate. Since gas exchange is impaired in pulmonary emphysema, the person in question will experience severe shortness of breath, particularly during physical exercise.
Trachea
The largest breathing tube in the body, passing from the throat down to the chest, where it connects to the two bronchi leading to the lungs.
Vaccine
An injection that protects the body from a specific disease by stimulating the body's own immune system.
Wheeze
A breathing sound that may be squeaky, whistling, or musical. Wheezes are often (but not always) a symptom of asthma. Wheezes are due to air passing through a narrowed opening and are therefore usually accompanied by difficulty breathing.
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