Did you know that our lungs have a sort of odor detector?
Now, this doesn't mean our lungs aid in our sense of smell. Instead, rhe odor receptors in our lungs are located on neuroendocrine cells, which are like little flasks that contain hormones. When the receptors on these cells detect offending smells, they don't report to the brain like the neurons in our noses. Instead, they automatically secrete chemicals that cause the airways to constrict.
Even though constricting airways may sound like a bad thing, they're a mechanism that protects us from inhaling dangerous substances. When our environment turns dangerous, our airways respond by constricting in order to limit our exposure to harmful substances and to help us cough them out if necessary.
- Odor Receptors Exist In The Lungs, Too (Huffington Post)