How can smoking kill humans?
Smoking is known as the silent killer, it earned that name for the 5.4 million people that it kills per year. It is said that in the 21st century 1.6 billion people will die because of harmful smoking. Smoking can kill humans in many different ways and three of those ways are cancer, heart attacks and passive smoking.
Smoking increases the risk of over a dozen cancers including lung cancer, cancers of themouth,larynx(voice box),pharynx(upper throat), nose and sinuses,oesophagus(food pipe) , liver,pancreas, stomach,kidney,bladder , cervixandbowel, as well as one type ofovarian cancerand some types of leukemia. But for now let us concentrate about the type of cancer that a smoker is more likely to get lung cancer. ("Smoking and Cancer")
Lung cancer is the No.1 killer among all types of cancer. It is estimated that lung cancer will account for about 15% of all new cancer cases in 2008, but will cause nearly 30% of all cancer deaths. Over the past three decades, little improvement has been achieved in extending lung cancer patients' lives. In 1975-1979, 35% of people survived one year or longer after initial diagnosis; 25 years later (2000-2003), this number had only improved to 41%.
Smoking is also the cause of many heart attacks. A heart attack happens when a person's heart muscle stops beating. You need to get oxygen to your heart to keep it alive. If a person's heart stops for too long, severe damage to the heart muscle can result. Smaller versions of heart attacks, or infarctions, may not cause immediate death, but a heart will develop excessive scar tissue in the place of normal tissue. A person needs a certain amount of normal heart tissue and muscle for it to work properly. Smoking causes a wide array of heart-related diseases because it can promote the degeneration of the cells. (Leonard)
Not only that but the nicotine present in the smoke can generate heart diseases because it Decreases oxygen to the heart; Increases blood pressure and heart rate, Increases blood clotting and damages many blood vessels.
Most of the 1.5 million heart attacks in the United States every year are caused or complicated by severe atherosclerosis, a narrowing of the arteries that makes it easier for clots to form and block blood flow to the heart. In as many as 150,000 heart attacks every year, however, there is no significant hardening of the arteries, and "the vast majority" of these patients are smokers.(Smokers Who Appear Healthy Risk Heart Attack)
Smoking does not only effect the smoker but it effects others around him as well. This process is called passive smoking. Passive smoking is the inhalation of smoke from a cigarette that someone else is smoking. It is also the third leading preventable cause of death in the United States. (WilliamsE2) studies in recent years showed thatpassive smokingwas causing 3,000 to 5,000 lung cancer deaths a year in nonsmokers. Now a study estimates that the toll frompassive smoking, including deaths from heart disease and other cancers, may be 10 times that. (Raeburn p.3)