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 cigarettes leads to actual physical dependence. This can cause unpleasant withdrawal symptoms when a person tries to quit. Nicotine replacement therapy (NRT) gives you nicotine â in the form of gums, patches, sprays, inhalers, or lozenges â but not the other harmful chemicals in tobacco.