Neuroscience for Kids states that smoking affects the nervous system by causing an increase in blood pressure, heart rate and respiration as well as constriction of arteries and stimulation of the central nervous system. Long-term exposure to tobacco results in addiction and dependence and also increases a person’s risks of getting cancer.
Tobacco smoke contains nicotine, which attaches to small tar particles and reaches the lungs, explains the Neuroscience for Kids. The lungs absorb nicotine quickly, allowing nicotine to reach the brain around eight seconds after a person inhales tobacco smoke. Nicotine reaches the central nervous system in around three to five minutes when tobacco is chewed. American cigarettes generally consist of 9 mg of nicotine; however, much of this nicotine is burned off, causing a smoker to absorb around 1 mg of nicotine in each cigarette.
Neuroscience for Kids says that nicotine acts on the central and peripheral nervous systems, and it can be stimulating or relaxing depending on a person’s mood and dosage. Smokers become addicted and dependent after long-term exposure to tobacco and nicotine. The prevailing theory on how nicotine results in addiction and dependence is that nicotine affects the limbic pathways in the brain that use the neurotransmitter dopamine, causing some of its addictive properties.