Unexpected Disorders Of The Respiratory Tract Airways Biology Essay

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Asthma is considered to be one of the unexpected disorders of the respiratory tract airways which, infact threatening the life of many people of different ages especially young children and sexes. The diseases is mainly due to two obstacles, where the first one is occur through the constriction of muscles surrounding the lungs leading to difficulties in breathing. The second is due to inflamed airways that become very swollen and irritated with the production of heavy mucus, especially when the symptoms are worsen and finally both complications could result the patient starts suffering wheezing, difficulties in breathing, lung muscular pain, coughing and tiredness. Ortega et.al. (2002).

The diseases also occur by different cause and majority of them are unknown. Normally the human body requires oxygen which is acquired from the air and it is very essential for the cells to perform their function properly and ultimately helps maintaining the airflow during the breathing process. During asthma occurrence the bronchial passage is narrowed completely blocked, this will prevent the inspiration as well as the expiration of the air by the lungs.

In some occasion for example, the people themselves can realize the reason behind the cause, especially when they are exposed to different unhygienic environments which are contaminated with various airborne allergens such as dirty dust, presences of variety insects and direct human contact especially the children with different

animals including dogs, mouse as well as cats. Phipatanakul et.al (2004).

The diagram below illustrate the difference between normal and asthmatic bronchiole, where in later the smooth muscle constriction within the walls of the bronchioles constricts and disrupts the airway passage leading in breathing difficulties. Figure. 1

Literature review

Different scholars have put their experiences and effort explaining the asthma disorder causes, some researcher described that the hygiene hypothesis of people living style and their education contributed in increasing of such diseases in the community and that was due they are not exposed to any sort of infection as this play an important role in strengthen the immune system when they are compared to a previous people as explained by Shabaraya et.al. (2008) .

Other scholar have revealed that there are an strong relation between some factors and asthma occurrence and these includes different flammable and corrosive chemical that are used in many laboratories for different purposes and investigation, strong drugs, direct or accident exposure to unstable climate and different types of infections as described by Vijaykumar et.al. (2009).

Several recent researchers have also emphasised on the affect and changes in ladies hormones function including thyroid hormones could share it the elevation of the asthma pathogenesis as expressed by Camargo et.al. (1999).

Pathophisiology of Asthma

People could be encountered with many unrealized circumstances that might have positively or negatively affect on that particular individual and the person who is suffering from asthma will lead as mentioned earlier the airways becoming very irritable and sensitive as well due to highly inflamed lungs causing difficulties or breathing incomfortibility. Naturally in any inflammation, the body starts realesing the important inflammatory cell mediators as a indicators of infection or inflammation including histamine, tryptase leukotrienes and prostaglandins which will automatically triggered as soon as esexposed to allergens, cold air. This mediator's will directly released from different tissues and cells such as bronchial mast cells, alveolar, macrophages, T lymphovytes and epithelial cells. There are also other types of mediators with other function of causing acute brochoconstriction known as

"early phase asthmatic response". The inflammatory mediators also do further other function where it directly activate the first defenses line cells such eosinophils and neutrophils and their migration to the airways, where they cause injury. This process is called "late-phase asthmatic response" results in epithelial damage, airway edema, mucus hypertension and hyperresponsiveness of bronchial smooth muscle. Which finally leads to presence of recurrent symptoms like wheezing, chest tightness, breath

Difficulties. Shaji and Lodha (2008).

The diagram below shows the process of realising of different inflammatory cell meditations and macrophages toward any strange antigens. Figure 2.

Epidemiology and history of asthma:

The diagram describes and explains the distribution of the asthma in different countries and the common symptoms with it estimated percentages.

In recent year the increasing and prevalence of the inner respiratory tract diseases like asthma were considered to be the main complicated diseases that kill many patient especially the school children. Jaakola, et .al. (2004).

The epidemiology of the Asthma is further discussed below:

Asthma is a chronic inflammatory disorder of the lungs airways that almost affects around 14 to 15 millions local people of the United States. And it has been estimated that about 4.8 million children have asthma which makes it the most chronic disease of childhood.

The prevalence of asthma increased 75% from 1980-1994 and the rates in children under 5 years have increased more than 60% from 1980-1994.

Asthma causes over 500.000 hospitalization nearly 2 million emergency room visits, and about 5.500 deaths each year.

Over the last 20 years the prevalence of asthma in the Unites States has increased dramatically. In 1970 national survey by the public health service estimated that 3% of the United States population had asthma approximately 60% of these asmathtic had consulted a physician for asthma during the previous year and approximately 50% were using a medication or treatment for asthma. (Bierman et al., 1996).

In 1996 there were 14.6 million people with asthma 4.4 million of whom were less than 18 years old (Adams,Hendershot and Maranao 1999).Asthma is the third most prevalent chronic disease after respiratory allergies and recurrent ear infections and is responsible for approximately 10.1 million days lost from school, during 1996 asthma was the first list diagnosis in 474,000 hospitalizations(Graves and Kuzak 1998).

5.4 million people in the UK are currently receiving treatment for asthma.

1.1million children in the UK are currently receiving treatment for asthma.

There is a person with asthma in one in five households in the UK.(Warrell et al.,2005)

Asthma in children:

in the united state over 9 million children have been diagnosed with asthma, as it is the most prevalent chronic conditions in childhood and it is the most common cause of hospitalisation of children under the age of 15.

Asthma in children differs from child to another. Some have mild asthma, while others have severe asthma. The child may have airway swelling all the times even if he feels fine. There is no cure for asthma, but it can be controlled by certain medication. Some medicines can help the child's airway by keeping them wide and open and by decreasing the inflammation. Asthma in children may change in time, in other conditions asthma will outgrow when the child grow up. (www.pdrhealth.com)

The exact cause of asthma is not known, if anyone in the family has asthma the child has more chance to get it. When the child has allergies or over sensitive to something around him, he will be likely to have asthma. However, not all children with asthma have allergies.

The child's asthma or asthma attach in children May leads to certain symptoms such as:



Shortness of breath

tight feeling in the chest


These symptoms may occur for few years and stop, while others may have attacks for longer period of time. The mild asthma can be controlled by reliever inhaler. However in severe attacks of asthma symptoms can develop to:

Difficulty in talking

Skin around the neck and chest looking "pulled in" and "stomach breathing" this because the child uses extra muscles to help them to breath

Grey or blue finger nails

Very wide nostrils

Faster heart beat than normal


Children are at higher risk of airway obstruction and often respond poorly to bronchodialators the size of the airways in children under age of 5 years is smaller than in adults; because of their smaller calibre edema mucous and cellular debris can cause significant increase in obstruction in the airways of children than in those of adults. The chest wall of young infants is less rigid than that of an adult and relative lack of elastic recoil predisposes the young infant to early airway closing even during tidal breathing. (Korenblat et al, 1992)

Contributing factor of asthma:

Asthma is a complex condition and its causes are not fully understood, the risk factors to asthma can be classified in to three main factors:

1-Host factors that predispose an individual to asthma, which are:

Genetic predisposition

Although environmental factors are clearly important determinants of asthma few studies have showed that asthma has strong genetic component but does not follow monogenic patterns of inheritance. Interleukin (IL)-4 genetic variants in the promoter region of the) IL-4 gene have been related to elevated immunoglobulin(Ig)E levels. The polymorphism involves a C-T substitution in the promoter region on chromosome 5q31 resulting in increased responsiveness to IL-4 this locus has been associated with asthma diagnosis in some studies.IL-13 polymorphisms within the IL-13 gene are associated with high IgE levels and with the presence of asthma.IL4-Rα on chromosome 16 is a shared component of the receptor for both IL-4 and IL-13 and polymorphisms in this gene are also associated with asthma and atopy.It is of interest that different asthma associated traits are associated with individual polymorphisms that affect splicing of IL4-Rα.Gene-gene interactions rarely have been studied but recently an interaction between polymorphisms in IL4-Rα and IL-13 was reported to increase the risk of asthma fivefold.(Bracken,2002)

Gender as a factor

Asthma in early life tends to be predominantly male disease whereas asthma in later life tends to be more common in females; this was confirmed by epidemiological data. The male to female ratio of asthma is 2 to 1 until age of 10 at age of 14 the ratio becomes mostly equal. Following puberty asthma ratio in females is higher. The exact reason for the gender difference in asthma are unknown but are likely to relate to hormonal, mechanical and differing host response to environmental exposures.(Beirman,1996)

2-Trigger factors which are environmental factors that precipitate asthma exacerbations and/or cause symptoms to persist and the factors are:

Asthma diet

For years, there was thought to be no or little connection between developing and controlling asthma and what a person ate. However, research has shown that there may be connection between certain foods and ways of eating to susceptibility asthma attack.

Vitamins and nutrients:

Rates of asthma levels has been increase in the UK over the past 20 years, and many researchers and doctors suspect that this increase has something to do with diet. Most people have been eating more processed food and less vegetable, which may be one of the causes of asthma.

People who eat food high n vitamins E and C, beta-carotene, omega-3 acids and flavoroids have in general, lower rates of asthma. Teenagers who don't get enough of these vitamins and nutrients have more chance to develop lung problems. One way to improve your eating habit is by having enough essential nutrients by eating fresh vegetable every day, especially leafy greens such as spinach.(www.ehow.com)


While increasing the consumption of vegetable helps the intake of vitamins C and E and their nutrients that help in the fight against asthma. Dairy consumption is thought also to help you breath easier. Researches from the New Zeland based group international study of asthma and allergic in childhood conducted testes for 10 years on more that 700,000 children who get more calcium from food were the least likely to develop asthma. Doctors in England have also noted that not only calcium but the high level of magnesium count in milk was able to help people with asthma.

A study of more that 2.000 adults showed that those who consumed more that 100mg above the mean average experienced increase air flow and calmer lungs. By increasing the amount of low fat dairy such as milk may help to avoid asthma attacks. (www.ehow.com)


Fish are generally high in omega-3 fats, but most of Americans eat more amount of omega-6 which is found in many prepare chips, cookies, salad dressing and cakes. Omega-6 causes the body to over produce cytokines which inflame the lungs and make them overly sensitive to dust and other irritants. On the other hand, omega-3 slows the production of cytokines and calms the airways which reduce instant for asthma problems. Eating more fish could control or avoid you from asthma attack. (www.ehow.com)

3-Casual factors which are environmental factors that influence susceptibility to the development of asthma in predisposed individuals and the factors are:

Asthma can be triggers and exacerbated by exposure to many environmental factors. These environmental factors divided into:

Indoor air pollution

Outdoor air pollution

Indoor air pollution

In industrialize countries, adults and children spend most of their time indoors. Expose to indoor air pollution my have more important effect on childhood asthma than exposure to outdoor air pollutions. The primary indoor air pollutions associated with asthma rise divided into:

Biological allergens

Biological allergens can be found throughout home, workplace, and school for example:

Dust mites: sensitization to house dust mites is an important risk factors for the development and increase of asthma. The dust mites grow optimally at worm temperature and with humidity greater than 50% in cloth covered objects.

Cockroaches: cockroches allergens may increase the risk of developing asthma. Cockroach dropping could be the worse allergens n the indoor environment. A 36% cockroach sensitization rates has been reported in asthmatic children.

Cats: exposure to cats is causally related to asthma exacerbations among many children with asthma. The severity of allergic reactions to cats is greater than reaction to other domestic pets. More than 6 million U.S residents have allergies to cats.

Other animals: dogs, rodent, bird, and other furry or feathered animals in the house my contribute in varying degree to the animal allergens within the house. Dogs may have breed specific allergens and it is less than cats alleges. Birds and feathers have been suggested as allergenic; however, it may be that the dust mites associated with feathers

Molds: exposure to molds can lead to allergenic sensitization and can exacerbate asthma or allergic rhinitis. At least 60 species of mold have spores thought to be allergic. Species for particular concern are:





Environmental tobacco smoke (ETS): exposure to (ETS) is a risk factor

for asthma attack in children. Children with asthma and whose parents smoke have more frequent asthma attacks and more sever symptoms. There is a clear evidence of an association between exposure to environmental tobacco smoke and the development and rise of asthma.

7. Combustion devices: improperly used of malfunctioning heating devices are major sources of combustion pollutants indoors. Some of these sources are:

- Insufficient furnaces

- Improperly vented fire places

- Stoved burning wood, coal and other biomass

- Improperly vented kerosene or gas space heaters.

The results of these combustion devices are:

Carbon monoxide

Nitrogen dioxide

Sulfar dioxide

Particular matter.

Although carbon monoxide is a major health concern, it is not an irritating gas and it is not likely by itself to exacerbate asthma. It is combined with another product it will exacerbate asthma symptoms.

Chemical fumes: some building materials and some furnishing contain formaldehyde. This may exacerbate asthma in some infants and children. At sufficient amount in the air, cleaning products such as chlorine and amino would also trigger the reaction.

9. Miscellaneous allergens: latex can also cause an allergic response either by inhalation of the particles or by direct contact. Symptoms vary from skin eruption to bronchospasm and anaphylaxis. Gloves, balloons and various types of sporting equipment may trigger allergic responses around the home.


Out door air pollutions

For the last several decades, high levels of outdoor air pollutions have been associated with short term increase in asthma mortality and morbidity. Specific exposure to outdoor plant allergens such as organic dusts from castor beans, soybeans, and grains dramatically illustrate this relation ship. Ambient hazardous air pollutant, as well as industrial release of aldehydes, metals, isocyanate, and others have been shown to cause and triggers asthma.

Traffic release pollutants and diesel exhaust

Exposure to motor traffic emissions can have a significant effect on respiratory function in children and adults.

Studies shows that children who live near heavily traveled road ways have more rates of wheezing and diagnosed asthma. A child riding in a school hus may be exposed to as much as four the level of diesel exhaust as one riding a car. (www.asthma.org.uk)

Asthma mortality and morbidity:

After a long period of steady increase, evidence suggests that asthma mortality and morbidity rates continue to decrease. The number of death due to asthma in 2002 was approximately 8.5% lower than the number of death seen in 1999.Hospital discharges have been declining since 1995 and 2002 the hospital discharge rate has declined 13% since it peaked at 19.5 per 10,000 in 1995.However, asthma remains a major public health concern. In 2003 approximately 20 million Americans had asthma and the condition accounted for an estimated 12.8 million lost school days in children and 24.5 million lost work days in adults. Asthma ranks within the top ten prevalent conditions causing limitation of activity and costs U.S nation $16.1billion in health care costs annually.(American Lung association,2005)