Emphysema

Causes of Emphysema• Normal lung tissue stretches when we breathe in and

springs back when we breathe out (elastic recoil).

• In emphysema the elastin becomes permanentlystretched and the lungs cannot force out the air.

• The alveoli surface area is reduced and they can burst.• It occurs in 1 in 5 smokers and develops slowly over a

period of 20 years…

Normal Alveoli Emphysema

Symptoms of Emphysema• Shortness of breath due to the difficulty of exhaling air with

reduced lung elasticity. As a result it is difficult to inhale fresh air containing oxygen so the patient feels breathless.

• Rapid breathing as the smaller alveoli surface area results in reduced oxygen levels in the blood so the patient breathes rapidly to try to increase the oxygen.

• Chronic cough due to the body trying to remove damaged tissue and mucus which cannot be removed.

• Bluish skin colour due to low levels of oxygen in the blood as a result of poor gas diffusion in the lungs…

Pulmonary Fibrosis

Pulmonary Fibrosis• Caused when scars form on the epithelium lining of the

lungs causing them to become thickened.

• This reduces the efficency of oxygen uptake by the blood (Fick’s Law), as the diffusion pathway is increased.

• Also the volume of lungs that the air can contain is reduced.

• The scars also reduce lung elasticity meaning that after breathing in, the lungs don’t spring back. So air is not

expelled from the lungs as well…

Symptoms of Fibrosis• Shortness of breath especially when exercising as

much of the lung air space has been replaced by scar tissue.

• Chronic dry cough because the scar tissue causes anobstruction which the body tries but cannot remove.

• Pain and discomfort in the chest due to the pressure and damage from scar tissue and persistent cough leading to more damage.

• Weakness and fatigue due to reduced oxygen intake,resulting in reduced cellular respiration…

Asthma

• Asthma is the result of a localised allergic reaction.

• It affects up to 10% of the world population.

• It accounts for 2000 deaths each year in the UK.

• It is caused by common allergens like pollen, animal fur, faeces of house dust mites.

• It can also be triggered or made worse by air pollution(e.g. sulfur dioxide, nitrogen oxides and ozone), cold air,

infection anxiety and stress.

Effects of Asthma on bodyThe allergen causes white blood cells in the linings of the bronchi and bronchioles to release a chemical called histamine causing:

• the lining of the air ways to become inflamed.

• the cells of the epithelial lining to secrete larger amounts of mucus than normal.

• fluid to leave the capillaries and enter the airways.

• the muscle surrounding the bronchioles to contract and constrict the airways.

Symptoms of Asthma• Greater difficulty in breathing because of the

constriction of the bronchi and bronchioles, their inflamed linings and the additional fluid and mucus.

• A wheezing sound caused by air passing through constricted bronchi and bronchioles.

• A tight feeling in the chest due to being unable to ventilate the lungs adequately due to the constricted airways.

• Coughing as a reflex response to try to clear obstructed bronchi and bronchioles…