The Pathway. 1  Air enters the nostrils. 2  passes through the nasopharynx, 3  the oral pharynx.  through the 1  glottis. into the trachea.  into the right and left bronchi, which branches and rebranches 1  into. bronchioles, each of which terminates in a cluster  of. alveoli.
As the body adjusts to less caffeine, these symptoms should subside. Nicotine May Cause Less Sleep. Nicotine is also a stimulant, and nicotine side effects can cause insomnia and withdrawal symptoms similar to caffeine. Smoking may also create other sleep disturbances.
The nicotine in cigarette smoke is addictive. When used in small amounts, nicotine creates a pleasurable feeling, which makes you want to smoke more. The more you smoke, the more you crave. One of the major problems is when you want to quit, you suffer withdrawal symptoms. You may experience headaches, nervousness, irritability and difficulty sleeping. Nicotine can also affect your mood, because it alters the chemistry of your brain and central nervous system.