Smells and Bells

In class today Doctor Herz referred to taste and smell as the "chemical senses," because they are used to detect and perceive the actual molecules of a substance in a way that the brain can understand -- the chemical senses literally sense chemicals. However, detecting a substance first requires that it be internalized (whether in the mouth or nose), which contributes to the perception of these senses as "lower." Personally, though, I think its really cool that our bodies come equipped with their own molecular scanners. That is, after all, what these chemical senses are doing when they analyze the molecular composition of a substance. Taste and smell are designed so that they detect different types of substances and provide information about them -- smell detects small hydrophobic and lipophilic molecules in the air while taste detects the hydrophilic molecules dissolve in our saliva. This difference in what the two senses detect helps explain those things t...