Biology

Respiratory Disorders

There are a number of respiratory disorders which affect people. The percentage of such disorders is particularly high in Pakistan. It is due to the more concentration of air pollutants not only in the urban but also in the rural atmosphere. Some of the important respiratory disorders are described next.

1. Bronchitis

Bronchitis is the inflammation of the bronchi or bronchioles. It results in excessive secretions of mucus into the tubes, leading to the swelling of tubular walls and narrowing of tubes (Fig. 10.8). It is caused by viruses, bacteria or exposure to chemical irritants Figure 10.8: Bronchi; normal (e.g. tobacco smoke).

Bronchi; normal left and inflamed right
Bronchi; normal (left) and inflamed (right)

There are two major types of bronchitis i.e. acute and chronic. The acute bronchitis usually lasts about two weeks and patients recover with no permanent damage to the bronchi or bronchioles: In chronic bronchitis, the bronchi develop chronic inflammation. It usually lasts for three months to two years.

The majority of people diagnosed with chronic bronchitis are 45 years of age or older.

Symptoms of bronchitis include a cough, mild wheezing, fever, chills and shortness of breath (especially when doing hard job).

2. Emphysema

Emphysema is the destruction of the walls of the alveoli. It results in larger sacs but with less surface area for gaseous exchange (Fig. 10,9). As lung tissue breaks down, the lungs do not come back to their original shape after exhalation. So air cannot be pushed out and is trapped in the lungs.

The Alveoli; normal (left) and emphysema (right)
The Alveoli; normal (left) and emphysema (right)

The symptoms of emphysema include shortness of breadth, fatigue, recurrent respiratory infections and weight loss. By the time the symptoms of emphysema appear, the patient has usually lost 50% to 70% of his / her lung tissue. The level of oxygen in blood may get so low that it causes serious complications.

3. Pneumonia

Pneumonia is an infection of lungs. If this infection affects both lungs then, it is called double pneumonia. The most common cause of pneumonia is a bacterium, Streptococcus pneumoniae. Some viral (influenza virus) and fungal infections may also lead to pneumonia.

When the causative organisms enter the alveoli, they settle there and grow in number. They break the lung tissues and the area becomes filled with fluid and pus. The symptoms of pneumonia include a cold that is followed by a high fever, shivering, and a cough with sputum production. Patient may become short of breath. The patient’s skin colour may change and become dusky or purplish. It is due to poor oxygenation of blood.

Prior to the discovery of antibiotics, one-third of pneumonia patients died from the infection.

Vaccines are available to prevent pneumonia caused by S. pneumoniae. Antibiotics are used in the treatment of this type of pneumonia.

Pneumonia
Pneumonia

4. Asthma

Asthma is a form of allergy, in which there is inflammation of the bronchi, more mucous production and narrowing of the airways (Fig. 10.11). In asthma patients, the bronchi and bronchioles become sensitive to different allergens (allergy causing factors) e.g. dust, smoke, perfumes, pollens etc. When exposed to any of such allergens, the sensitive airways show immediate and excessive response of constriction. In this condition, the patient feels difficulty in breathing.

The symptoms of asthma vary from person to person. The major symptoms include shortness of breath (especially with exertion or at night), wheezing (whistling sound when breathing out), cough and chest tightness.

The chemicals with ability to dilate the bronchi and bronchioles are used in the treatment of asthma. Such medicines are given in the form of inhalers.

Asthma
Asthma

5. Lung Cancer

Lung cancer is a disease of uncontrolled cell divisions in the tissues of the lung The cells continue to divide without any control and form tumours. The cellular growth may also invade adjacent tissues beyond the lungs. The most common symptoms are shortness of breath, coughing (including coughing up blood) and weight loss.

Lung cancer is the most common cause of cancer-related deaths and is responsible for more than 1.3 Millions deaths worldwide annually.

The main causes of any cancer include carcinogens (such as those in cigarette smoke), ionizing radiation and viral infection. Smoking is the main cause of lung cancer. This risk of lung cancer is significantly lower in non smokers Cigarette smoke contains over 50 known carcinogens.

Lung Cancer
Lung Cancer

Passive smoking (the inhalation of smoke from another’s smoking) is also a cause of lung cancer. The smoke from the burning end of a cigarette is more dangerous than the smoke from the filter end.

Eliminating tobacco smoking is a primary goal in the prevention of lung cancer. The World Health Organization has called the governments to stop tobacco advertising to prevent young people from taking up smoking.

If a person stops smoking, the chance to develop cancer decreases as damage to the lungs repaired and contaminant particles are gradually removed.


Bad Effects of Smoking


Smoking is harmful due to the chemicals in cigarettes and smoke. Tobacco smoke contains over 4,000 different chemicals, out of which at least 50 are carcinogens and many are poisonous.

Nicotine is a powerful poison and widely used as an insecticide in to past. When inhaled through tobacco smoking, it reaches our circulatory system and not only hardens the wall of the arteries but also damages the brain tissues.

Many people think that lung cancer is the only smoking-related disease and it is the number one cause of death among smokers. But it is not right. Cigarette smoke affects the body from head to toe. Smokers have a much higher risk of developing a number of life threatening diseases.

According to the WHO, the rates t smoking have declined in developed world. In the developing world, however, it is rising by 3.4% year as of 2002 survey.

Normal Lung and Smoker Lung
Normal Lung and Smoker Lung

Smoking may also lead to the cancers in kidneys, oral cavity, larynx, breast, bladder and pancreas etc. Many chemicals in tobacco smoke damage the air passageway, which leads to emphysema and other respiratory disorders.

The World No Tobacco Day is observed on the 31” of May every year.

Smoking also has effects on the circulatory system. The carbon monoxide present in tobacco smoke lessens the oxygen-carrying capacity of haemoglobin. Many other chemicals in smoke increase the production of blood platelets. When platelets are more than the normal numbers, they make the blood viscous and it can lead to arteriosclerosis.

Non-smokers who are exposed to second-hand smoke (passive smoke) at home or at work increase their heart disease risk by 25-30% and their lung cancer risk by 20-30%.

Smokers are at greater risk of developing infections, particularly in the lungs. For example, smoking increases the risk of tuberculosis by two to four times, and of pneumonia by four times.

Smoking also affects the social life of a person. Smokers may face social un acceptance because other people may not want to be exposed to other’s smoke.

Smoking is also responsible for weakening smoke. and staining the teeth. Tooth loss is 2 to 3 times higher in smokers than in non-smokers.

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