As compared to controls, elevated nasal levels of ACE2 and TMPRSS2 were associated with a 3.6-fold increased risk of SARS-CoV ...

Ahh. Let's continue. On the roof of the nasal cavity is the olfactory epithelium, which contains nearly 40 million special receptors that are sensitive to odor molecules traveling through the air.

The air that enters the nasal cavity flows down the trachea. The trachea has a number of adaptations: cartilage rings in the walls of the trachea help to keep it open ciliated epithelium and ...