Effects of Smoking on the Mammalian Gas Exchange

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Effects Of Smoking On The Mammalian Gas Exchange

During the First World War, a lot of men started smoking and more women started smoking too during the 1940s and 1950s. Years later, it became apparent that certain diseases, such as chronic bronchitis, emphysema and lung cancer became a lot more common. Cigarette smoke contains over 4000 different chemicals. Many of these are harmful, including tar (a mixture of chemicals including carcinogens, which cause cancer), carbon monoxide and nicotine. This is why smoking causes a lot of diseases, which often lead to death. Each year, about 100000 people in the UK die due to smoking.

Tar
Tar settles on the delicate lining of the airways and alveoli. Thus, the diffusion distance for oxygen entering the blood and carbon dioxide leaving the blood increases. Too much carbon dioxide can turn the blood acidic and a lack of oxygen causes various organs and processes in the body to suffer impairment from oxygen deficiency. Also, the presence of the chemicals in tar may cause an allergic reaction. This would cause the smooth muscles in the walls of the airways to contract and the lumen of the airways would get smaller, which would restrict the flow of air to the alveoli. On top of that, tar paralyses cilia, disabling them from moving the layer of mucus away and up to the back of the mouth. The bacteria and viruses in the mucus cannot be removed and can eventually block the bronchioles and infections of the lungs are more likely. Frequent infections inflame the lining and the layer of epithelium and also attract white blood cells, which release enzymes in order to move out of the blood and into the airways. These enzymes then digest parts of the lining of the lungs, so elastic tissue in the lining of the lungs is damaged. When this happens in the alveoli, elasticity of the alveolus wall is reduced and during exhalation, it does not recoil to push the air out, so air is trapped in the...
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