The nicotine from the tobacco plant is currently killing around 4 million people every year.
Nicotine comes from the tobacco plant and is addictive, more addictive in fact than crack cocaine. This means that when you are hooked your system requires that a certain level of nicotine must be kept in your bloodstream or you start feeling uncomfortable. This happens when you pass your normal time for another hit.
You need this hit of nicotine to maintain your comfort level in the same way as a diabetic needs insulin. The difference is that when you quit smoking, your body will adjust to doing without nicotine and you can be comfortable without needing any further hits.
While you are hooked nicotine does a number of things to your system. Nicotine activates neurohormonal pathways, releasing acetylcholine, norepinephrine , dopamine, serotonin, vassopressin, beta-endorpin, growth hormone, and ACTH. But nicotine can do other things too: it may cause and delay the healing of peptic ulcers; it can cause liver or kidney damage and may interfere with your processing of insulin. The high blood pressure caused by nicotine can also develop into malignant hypertension, the uncontrollable blood pressure that results in death. Discontinuing smoking does not directly reduce blood pressure, but is very important for people with hypertension because it reduces the risk of many dangerous outcomes of hypertension, such as stroke and heart attack.
Cigarette smoking during pregnancy is associated with an increased risk of spontaneous abortion, low birth weight infants and perinatal mortality. Nicotine is considered to be the most likely mediator of these outcomes. Scientists have known that children of women who smoke during pregnancy can develop hearing-related cognitive deficits. Now for the first time, researchers believe they have evidence that not only implicates nicotine as the culprit, but also shows what the substance does to the brain to cause these deficits. It also increases the incidence of atherosclerosis, strokes, and peripheral vascular disease. Diseases of the lungs—colds, flu’s, acute bronchitis, pneumonia, COPD (chronic obstructive pulmonary disease), which includes emphysema and chronic bronchitis, and lung cancer—are all much more common in smokers. Other infections or allergies are also prevalent and rapid aging of the body and especially the skin results from the generally poor oxygenation of tissues and the other chemicals and physiological effects of regular cigarette smoking. The modern cigarette is extremely complex. Each cigarette smoked delivers about 1 mg of nicotine. It contains everything from sugar to liquorice, chocolate, herbs and spices. There are 8000 or more chemicals that come out when you light it and having them delivered in the right ratios is a substantial engineering feat. Other harmful chemicals found in cigarettes include: Acetone – used in nail varnish remover, Ammonia – used in dry cleaning fluids, Arsenic – used in pest control and insecticides, Benzene – used in chemical manufacture, Cadmium – used in batteries and Formaldehyde – used to preserve dead bodies. Finally, while nicotine from a cigarette reaches the brain within 20 seconds and creates a dependency almost immediately, the good news is that nicotine is generally out of your bloodstream within three days after you stop smoking.