Smoking has a wide variety of health effects and can affect just about every organ in the body. But one of the organs that is most directly affected is the lungs. This is maybe not surprising as this is the organ in direct contact with cigarette smoke.
The lungs are organs of respiration. They are designed to carry air that contains oxygen and pass this oxygen to the blood stream. Everybody has two lungs that are divided into lobes.
When somebody starts smoking this causes irritation of the cells lining the air tubes within the lungs (the bronchi and bronchioles). One of the body's basic responses to this is to produce mucus. This mucus can reduce the diameter of the airtubes making it more difficult to breathe. Have you heard of a 'smoker's cough'? This is when a smoker coughs up this mucus.
In a healthy person, there are cells lining the lungs and upper respiratory tract that have small hair-like projections called cilia present. These beat to move dust and debris out of the lungs. They are a bit like the lung's own broom sweeping team. Smoking kills these cells so that their cleaning function is no longer carried out. Dust and particles can then accumulate which is one of the reasons that smokers often complain of respiratory diseases.
One of the gases in cigarette smoke is carbon monoxide. This gas interferes with the process of oxygenation of blood in the lungs. In fact if you inhale too much carbon monoxide you will suffocate and die. This gas is present in car exhaust fumes and is responsible for the deaths of many people each year using this as a form of suicide.
The air sacs in your lungs where oxygen is passed to the blood are called alveoli. These have a very large surface area - about the size of a tennis court. Every time that you smoke you kill some of these alveoli. These structures can't grow back, so once they are destroyed, that's it. Is it any wonder that smokers find it difficult to breathe due to minor exertion, such as walking up stairs?
The long-term effect of smoking on the lungs is quite well documented. Cancer of the lungs is largely due to smoking. It is estimated that 87% of cases of lung cancer in the US are smoking related. Smoking is the primary cause behind a condition called COPD (Chronic Obstructive Pulmonary Disease). Patients with this condition find it very difficult to breathe because their airways have become so obstructed.