Final answer:
CN I (olfactory) detects and transmits information about smells to the brain.
Step-by-step explanation:
The function of CN I (olfactory) is to detect and transmit information about smells to the brain. The olfactory receptor neurons, located in the olfactory epithelium within the nasal cavity, have dendrites that extend into the mucus lining. As odorant molecules are inhaled, they dissolve in the mucus and bind to receptor proteins on the dendrites, producing a graded membrane potential in the olfactory neurons. This information is then sent to the olfactory bulb of the brain, where it is processed and interpreted.