Final answer:
Olfactory sensory neurons are activated when odorant molecules bind to specific receptors, and they transmit electrical signals to the olfactory bulb. From the olfactory bulb, olfactory signals are sent directly to the olfactory cortex, frontal cortex, and thalamus for further processing.
Step-by-step explanation:
Olfactory sensory neurons are activated when odorant molecules bind to specific receptors on the cilia of the neurons. Each neuron has only one type of receptor, specialized to detect a specific odorant. When an odorant binds to its receptor, the sensory neuron is stimulated, and it transmits electrical signals to the olfactory bulb.
The olfactory bulb, composed of neural clusters called glomeruli, receives signals from different types of olfactory receptors. From the olfactory bulb, olfactory signals directly travel to the olfactory cortex, frontal cortex, and the thalamus. Unlike other sensory information, olfactory signals also directly reach the cerebral cortex, which is responsible for processing smell.
Overall, olfactory sensory neurons work through chemoreception, detecting odorant molecules and converting them into electrical signals. These signals are then transmitted to the olfactory bulb, and from there, they go to various regions of the brain for further processing.