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Despite the widespread knowledge of the harmful effects of smoking, the specifics of the damage caused by cigarette smoke and the substances involved remain obscure to many. Cigarette smoke is a complex concoction of numerous chemical substances, many of which pose significant harm to the human body. This article will delve into the composition of cigarette smoke, its impact on the respiratory system, and the risk factors associated with smoking and lung cancer.
A cigarette is more than just tobacco. It is a combination of multiple substances derived from tobacco processing and the manufacturing process of the cigarette itself. The smoke from a burning cigarette comprises a gaseous phase and a corpuscular phase, both laden with oxygen free radicals and toxic substances.
Over 4,000 different types of substances, originating from the incomplete combustion of the cigarette, have been identified. Among these, at least 40 have been classified as carcinogenic. The primary substances inhaled when smoking a cigarette include:
Nicotine: An alkaloid found in tobacco leaves, nicotine is responsible for the onset of psychophysical dependence on tobacco smoke. It reaches the lungs and pulmonary alveoli, enters the bloodstream, and eventually affects the nervous system, causing a sense of gratification. Nicotine also interferes with blood clotting and triggers hypertension and increased heart rate.
Carbon Monoxide: This gas forms during the combustion of cigarettes. It binds to the hemoglobin in red blood cells, replacing oxygen molecules, leading to decreased blood oxygen levels and increased heart rate.
Carcinogenic Substances: These are primarily found in the tar in cigarettes and the pesticides used during tobacco cultivation. They include polycyclic aromatic hydrocarbons, nitrosamines, aromatic amines, heavy metals, and even radioactive substances.
Irritants: Substances such as formaldehyde, ammonia, hydrogen cyanide, and acrolein are responsible for the onset of respiratory diseases.
Other toxic or potentially carcinogenic components present in cigarettes include acetone, arsenic, urethane, nitric acid, benzene, DDT, and methanol. It's worth noting that while the cigarette filter may limit the quantity of harmful substances inhaled, it does not block them completely.
Smoking alters the functioning of cilia, tiny hair-like structures in the respiratory tract, and leads to mucus stagnation. Mucus, produced by the respiratory epithelium, is crucial for preventing foreign substances from entering the lungs. The lack of ciliary action causes the mucus to stagnate, favoring the development of infections and promoting the onset of respiratory diseases.
Smoking also has a detrimental effect on the lungs. The radical oxygen species in smoke cause a state of chronic inflammation in the lungs, leading to the accumulation of immune cells. This persistent inflammatory state can lead to chronic obstructive pulmonary disease (COPD), a chronic and irreversible condition that affects the bronchi and lungs.
Moreover, the carcinogenic substances in smoke contribute to the development of various types of lung cancer. These substances can be categorized into direct-acting carcinogens, which cause immediate lung damage, and indirectly acting carcinogenic substances, which promote the onset of cancer over time through slow modifications.
The risk of developing lung cancer increases depending on several factors:
It's worth noting that the risk of developing lung cancer decreases gradually over 10-15 years for those who quit smoking. After this period, ex-smokers face a risk of developing lung cancer equivalent to the risk faced by non-smokers. However, passive smoking also increases the risk of developing lung diseases.
In conclusion, the dangers of cigarette smoke are manifold and extend beyond the commonly known effects. It's crucial to understand the composition of cigarette smoke and its impact on the respiratory system to fully comprehend the risks associated with smoking.