BIOS 286 Lecture 2: Olfaction 2
Document Summary
Osn is sensitive to odorants at the cilia but not elsewhere. Airborne (volatile) but must have some water solubility to pass the mucus layer. Apply odorant to dendritic knob with cilia: Produces an action potential in the soma and axon. The olfactory system (and chemosensory systems in general) evolved to detect and recognize biologically-generated substances. Most smells have emotional meanings (3/4 unpleasant signal danger, 1/4 pleasant signify food, sex, etc. ) Each or is a gpcr (g protein-coupled receptor) Most of the homology is found in transmembrane regions tm1-2-6-7. Most of the diversity is in the n-terminal region (extracellular) and tm3-4-5. Expression of or proteins in the olfactory epithelium. Or genes are only expressed in olfactory epithelium. Each osn expresses only one or gene out of 1000 possible. Osns expressing a given or are distributed randomly throughout the epithelium. Expression of one or prevents expression of the other or.
