The main prevention of TB is vaccination; children are routinely tested for their immunity. Social and economic measures are also included:
- better education about TB
- more housing of a better quality
- improved health facilities and treatments
- better nutrition to nourish the immune system
TB can be controlled with drug treatment. However, it occurs over a long period (6-9 months) and my cause the development of strains of the bacteria that no longer respond to the drug. Inactive TB involves drug treatment of one drug a day for 6-12 months, whereas active TB involves 6-7 pills a day for the same period of time, which can lead to liver damage
There is a high increase in the likelihood of disease if you have AIDS (+10%).
Pulmonary fibrosis
This arises when scars form on the epithelium of the lungs, causing them to become irreversibly thickened. This therefore means oxygen cannot disuse into the blood as efficiency because the diffusion distance has been increases and the volume of air that the lungs can contain has been reduced. Fibrosis also reduces the elasticity of the lungs, this also decreases the efficiency of the lungs and makes it harder to breathe and ventilate the lungs. The effects of fibrosis on the lungs:
- Shortness of breath, especially when exercising- a considerable volume of air space is occupied by fibrous tissue so less oxygen can be taken into the lungs with each breath. Diffusion is also extremely slow where the alveoli epithelium has been thickened. The loss of elasticity makes it hard to ventilate the lungs and therefore hard to maintain a diffusion gradient across the exchange surface
- Chronic dry cough- occurs because fibrous tissue and dead cells create an obstruction in the airways of the lungs, which the body tries to move by coughing
- Chest pain- a consequence of pressure and damage from the mass of fibrous tissue in the lungs, scarring due to coughing, and having to breathe harder to take in oxygen.
- Weakness and fatigue- due to the reduced intake of oxygen into the blood, released energy by cellular respiration is reduced.
The causes of fibrosis are unclear, but it may results from an excess of fibrous tissue, a result of injury or repeated harm to small areas or due to reactive processes.
Symptoms include:
- Shortness of breath
- Unproductive coughing
- Muscle pain
- Low grade fever
- Clubbed fingers and toes
- Loss of weight and appetite
- Fatigue and weakness
- Easy occurrence of infections
Macrophages cause certain types of fibrosis through over expressing a serine protease.
Asthma
This is an example of a localised allergic reaction. The most common allergens that stimulate asthma include: pollen, animal fur and dust mite faeces. It can also be triggered and made worse by other factors including: air pollutants (sulphur dioxide, nitrogen oxides and ozone), exercise, cold air, infection, anxiety and stress.
The above allergens cause white blood cells on the lining of the bronchi and bronchioles to release chemical called histamine, this causes:
- The lining of the airways to become inflamed
- Goblet cells secrete larger quantities of mucus than normal
- Fluid leaves the capillaries and enters the airways
- The muscles surrounding bronchioles contract, constricting the airways
This causes a greater resistance to the flow of air in and out of the alveoli, diffusion gradient is not maintained, this causes:
- Difficulty breathing- due to constriction of bronchi and bronchioles, inflammation and additional mucus/fluid.
- Wheezing- caused by air passing through the constricted airways
- Tight feeling in chest- lungs cannot be ventilated adequately
- Coughing- reflex response to the obstructed airways
Genetics contributes to the development of asthma. An increase in air pollution, dress and chemicals in manufactured products/food has led to a rise in the disease.
Asthma can be relieved using steroids or bronchodilators
Emphysema
This disease develops over a period of 20 years and is impossible to diagnose until lungs have been irreversibly damaged. Healthy lungs contain a large quantity of elastic tissue (made from protein elastin). It stretches when we breathe in and spring back when we breathe out. With emphysema, the elastin becomes permanently stretched; air cannot be forced out the alveoli. Surface area of the alveoli can decrease and they can sometimes burst, little gas exchange can occur. Symptoms of emphysema include:
- Shortness of breath- due to difficulty exhaling hair where lungs have lost elasticity, meaning it is difficult t inhale fresh hair containing oxygen. The smaller alveolar surface area means reduced oxygen levels in the blood, oxygen supply is attempted to be increase by rapid breathing
- Chronic cough- consequence of lung damage, body tries to remove damaged tissue and mucus that cannot be removed naturally because cilia have been destroyed
- Blush skin coloration- due to low levels of oxygen as a result of poor gas diffusion
