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.
Nicotine dependence is now recognized as a psychoactive substance dependence disorder (DSM-IV, ICD-10). Under the DSM-IV criteria smokers are classified as dependent if they exhibit impaired control and continue to smoke despite awareness that it exacerbates a medical condition, and if they experience withdrawal symptoms when abstaining from smoking, or if they have a history of unsuccessful attempts at quitting.