1. Faizan Kalwar

3. Basal cells – replace receptor neurons (a feature unique to the olfactory neurons) Sustenacular cells – scattered throughout epithelium, secretory granules empty contents on mucosal surface Receptor neurons

4. - Humans have ~40 million - Bipolar neurons - Dendrites extend into mucosal surface -Cilia on surface of dendritic knobs -Receptors on cilia make contact with odorants -One receptor for each neuron - Axons lead into glomerus

5. -Odor molecule binds to receptor protein on surface of cilia -Receptor conformation changes  activates G-protein (G olf ) -Adenylate cyclase activation produces cAMP -cAMP opens ion channels  Na + and Ca 2+ enter - Depolarization occurs at dendritic region which leads to generation of an action potential

6. -Activation of multiple receptors allows molecules that have never been encountered to be characterized -ORNs are sensitive to a subset of odorants which makeup its tuning curve - Some ORNs are very selective while others are much broader -Different thresholds exist for a given odorant between neurons with the same receptor - Adaptations occur