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.
Withdrawal symptoms can start as early as a few hours after your last cigarette, and often intensify over the next few days. Many people continue to smoke to help prevent withdrawal symptoms. Over time, continued nicotine use produces long-term changes in the brain that cause addiction. Nicotine lozenges can help to gradually lessen your dependence on nicotine.