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.
It constricts blood vessels to help relieve allergy symptoms and headache, hence its inclusion in many over-the-counter medications. Other effects may include insomnia, jitteriness, nausea and rapid heart rate. Like caffeine, nicotine constricts blood vessels and speeds heart rate and cognitive functioning. It attaches to acetylcholine receptors in the brain, often leading to additional effects like appetite suppression, nausea and dry mouth.