Asthma

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Biology 103
2001 Third Web Report
On Serendip

Asthma

Jennifer Trowbridge

Breathing is a vital process for every human. Normal breathing is practically effortless for most people, but those with asthma face a great challenge. During an asthma attack, breathing is hampered, making it difficult or even impossible for air to flow through the lungs. Asthma is an increasingly common problem, and has become the most common chronic childhood disease. At least 17 million Americans suffer from it(1), and although it can be fatal, it is usually not that severe(4). There is no cure for asthma, but with proper care, it can usually be controlled.

As someone with Exercise Induced Asthma, I have personal experience with the topic. I have experienced most of the symptoms described in my research, tried many of the medicines, and have my asthma under control. This essay will first discuss the normal function of the lungs, and then proceed to explain how this is effected by asthma. The causes of the disease and the ways of controlling it will follow.

Normal breathing is controlled by the lungs and the chest cavity. Airways are tubes with muscle that contracts and relaxes wrapped around them, and this accounts for the motion of the chest that is associated with breathing. The diaphragm, which is located underneath the rib cage, along with the intercostal muscles, or those in between the ribs, control the movement of the chest cavity(6). When these muscles contract, the chest expands, which lowers the pressure inside the lungs. Since air moves naturally from high to low pressure, the lungs are automatically inflated. In order to exhale, the diaphragm and the intercostal muscles relax, causing the chest cavity to become smaller. The decrease in volume causes the pressure in the lungs to go up, forcing the air out into the lower pressured atmosphere.

When air enters one's mouth or nasal cavity, it moves through the trachea, or the tube that connects the mouth to the lungs (6). It is also often referred to as the "windpipe." The trachea then branches off like a tree. The first splits of this "tree" are the bronchi, and the smallest branches are called the bronchioles. Thus after air travels through the trachea, it then reaches the bronchi, and spreads throughout the bronchioles.

Small air sacks called alveoli are at the tips of the bronchioles. When air reaches them, the oxygen concentration is high, which causes diffusion into red blood cells travelling through pulmonary capillaries (7). The red blood cells then distribute the new oxygen to the rest of the body. When they reach the alveoli again, they exchange carbon dioxide (a form of cell waste) for new oxygen, and repeat the process. The carbon dioxide is moved through the bronchioles, bronchi, and trachea in the form of exhalation.

The bronchi and bronchiole tubes are loosely wrapped with muscle. During regular breathing, the muscles around these airways are relaxed (5). This allows air to flow freely through these passageways to the alveoli. However, during an asthma attack, air has trouble reaching the alveoli, which prevents the body from receiving oxygen. This is because the airways become smaller. Firstly, the muscles around the airways spasm and contract. This then causes inflammation of the bronchioles and bronchi themselves, which causes a mucus to be produced. (1)(4)(5). Therefore, three different factors contribute to the closing of the airways. When this happens, the person is having an asthma attack. The process is a somewhat normal reaction to allergies or exercise, but it is worse for asthma patients because they have hypersensitive lungs.

"To have asthma" simply means to be prone to having asthma attacks or asthmatic symptoms. Symptoms can include shortness of breath, wheezing, coughing, chest tightness, and other breathing troubles. It is deemed an attack when the lungs are under so much pressure that they have trouble functioning normally. During this time, it is harder to breathe out than in (5). Because carbon dioxide cannot escape and oxygen thus cannot get in, it makes the patient feel short of breath, or as though he or she cannot breathe. The effects of an asthma attack are usually temporary, and the disease itself can usually be controlled so that the person can lead a normal lifestyle.

The causes of the disease itself are hard to determine. The only thing that is known about who tends to get asthma is that it is often associated with heredity, meaning that it runs in a family, and atopy, or allergic reactions (1). I, for example, also have atopic dermatitis, a skin allergy. The causes of an asthma attack, however, are well understood by both doctors and patients. The most common of these include exposure to cold air, exercise, allergens (such as dust mite, mold pollen, and animal dander), tobacco smoke, some viral infections, and weather (1). Every asthmatic responds differently to triggers. This is especially true for those who are effected only by exercise, in which case they have Exercise Induced Asthma (EIA).

Exercise Induced Asthma causes the same symptoms as "regular" asthma, and can range from mild to severe. For some, persistent coughing is the only symptom(3). Patients in good condition often do not experience asthma until they engage in vigorous exercise (3), which implies that at least for EIA, it can be prevented to a certain degree. Some people begin to feel their asthma 3 to 8 minutes after starting exercise, yet most do not get symptoms until 5 to 10 minutes afterwards (9). Others suffer from "late phase" asthma symptoms, which can occur 4 to 12 hours after exercise (3). While there are effective ways to treat EIA, one good way to handle it is to only play sports that allow for intermittent rest times, such as baseball, tennis, and volleyball (9). Stopping usually lets breathing slow down, which in turns helps the muscles around the bronchi to relax.

Asthma regulation and prevention is perhaps the most important issues to most patients. The first and easiest way to control it is to avoid triggers. Even if an attack has begun, this is one of the smartest things a person can do. (4). For instance, if cold weather is triggering an asthma attack, the person should find a way to get into a heated place. Or in the case of EIA, the best thing to do is stop exercising, and symptoms usually go away.

The simple technique of avoidance and environmental control is usually effective, but it is not completely reliable. Furthermore, it usually requires changing one's lifestyle in order to accomodate asthma. For these reasons, asthma medications are both necessary and desired. Allergy, Asthma, and Immunology Online (4) suggests that the goals of asthma medication should be as follows: to end coughing, wheezing, and breathlessness, especially in the night and morning; to enable participation in normal activities, including exercise; to avoid Emergency Room visits and hospitalization; to avoid side effects of the medicine; to meet the patients needs for a good quality of life. (4).

There are two basic categories of asthma medicine. One is quick relief, which is used in the case of an attack. All asthmatics should have this type of medication available. The second is long term medication, which is intended to reduce the effects of asthma over time. (1). Quick relief medicines are usually inhaled. They reach the lungs rapidly and relax the muscles around the bronchi and bronchioles (10). A few examples of these short-acting, bronchodialator inhalers include albuterol, Maxair, Proventil, and Ventolin (4). (It should be noted that albuterol is the generic form of both Proventil and Ventolin.) Long term controllers are usually corticosteroids, or anti-inflammatory steroids, which can be taken orally or through an inhaler (8)(10). Drugs taken orally include Accolate, Singulair, Zyflo, and even prednisone (3). A few inhaled corticosteroids are AeroBid, Azmacort, Flovent, Pulmicort, and Serevent (4). Many asthmatics must use a combination of these medicines in order to keep attacks completely under control. For instance, even with just Exercise Induced Asthma, I take Singulair, Flovent, and albuterol during my soccer season. This generally controls my asthma, but heavy running, especially in heat, humidity, or cold, will almost always trigger some sort of attack.

In the general population, these medicines have proved to be very effective when correctly used. Nonetheless, inhalers are often used improperly (8). The patient must push down the inhaler and breathe in with perfect timing in order for the medicine to fully enter the lungs, which can be a challenge. When spacers are used, however, it is nearly impossible to use the inhaler incorrectly (8). A spacer is tube that attaches to the inhaler, where the medicine sits until the patient is ready to inspire.

Clearly there are many medicines and techniques available to help asthmatics. Asthma is a growing concern in the U.S., especially among African American and Hispanic populations. This can most likely be attributed to "poverty, urban air quality, lack of education, and inadequate medical care." (2). It is yet another reason that good quality medical care and air clean-up projects should be supported.

Although it tends to influence certain populations more than others, asthma effects the lives of many people. Attacks can be both harmful and frightening to patients, and need to be controlled. But with the help of environmental regulating and medication, most asthmatics, like myself, can continue to live normal lives without fearing asthma.

 

WWW Sources

1)Asthma and Allergy Foundation of America,What is Asthma?

2) Asthma and Allergy Foundation of America,Asthma Facts

3) Asthma and Allergy Foundation of America , Other Asthma Info

4)Allergy, Asthma, and Immunology Online,Taking Control

5)Children's Medical Center of UVA, How Attacks Happen

6)Marshall Brain's How Stuff Works Site, Lungs

7) Marshall Brain's How Stuff Works Site , Lungs Continued

8)American Lung Association, Five Asthma Medication Groups

9)National Jewish Medical and Research Center , Exercise Induced Asthma

10) Children’s Medical Center of UVA , Treating Asthma

 

 

Continuing conversation
(to contribute your own observations/thoughts, post a comment below)

01/25/2006, from a Reader on the Web

I am a person who has had asthma since I was very young. I am now quite concerned about the discussions I am seeing in the news about taking inhalers off the market because of ozone problems. My doctors have tried numerous interventions,but nothing has worked as well in my case as inhaled medications. There is nothing as frightening as not being able to breathe. I hope the people making policy will consider how it will impact the lives of people who depend on these inhalers for their lives.Thank you for listening.

 

Comments

Richard Friedel's picture

Asthma etiology

To doubt the accepted etiology of asthma would apparently seem to be a sacrilege, like accusing all medical doctors of being involved in a giant conspiracy or worse. However because of the vast dimensions of the asthma problem, one aspect should be considered.

It is established in research (Dr. Gwen Skloot) that an asthmatic has difficulty in inhaling. However eastern breathing techniques for improving the ability to inspire are not considered.

Consider the mechanism of inhaling (http://www.lrz-muenchen.de/~s3e0101/webserver/webdata/PPT3.pdf) an excerpt from “The Circulation System” by J. Steven Alexander Ph.D (http://www.sh.lsuhsc.edu/intragrad/slides/212/alexander/L15_alex.ppt). It is clear that on inhaling pressure in the abdomen is increased. It would therefore be logical to suppose that increasing such pressure would aid an inhale. This technique is a fundamental part of eastern breathing routines which refer to putting pressure on the Tanden (in Japanese) or the Dantian (Chinese) during an inhale. The fact that the Tanden cannot be anatomically recognized should not cause difficulty in view of the substantial circumstantial evidence of beneficial on breathing.

A further difficulty with accepted asthma etiology is that the extremely thoracic or collar-bone breathing in attacks might well be a failed but intelligent tactic of the body which in principle is correct but flawed by lack of abdominal pressure.

To me asthma itself can not be a mystery as long as an obvious scientific approach is ignored. Richard Friedel

Anonymous's picture

How do I know

I feel like I might have exercise induced asthma, but I am not sure. How did you initially find out?

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