PSYCH 9A Lecture Notes - Lecture 7: Thalamus, Cranial Nerves, Olfactory Bulb
Document Summary
The sense of smell is triggered by: Receptors in olfactory epithelium - a mucous membrane at the top of the nasal cavity. Send signals to glomeruli (where signals from the smell receptors converge) in olfactory bulb and beyond to olfactory cortex. Provide a means of communicating - pheromones - odorants that convey information to other members of the species. Contribute to flavor - because air carrying odorants can reach the nasal cavity through either the nose or opening back of the mouth. Odorant molecules => olfactory receptor neurons (olfactory epithelium) => mitral cells (olfactory bulb) => mitral cell axons project via the olfactory tract => piriform cortex, thalamus, etc. Each glomerulus receives input from just one receptor type, but each type of receptor has a preferred odorant (although can bind with more than one odorant). Each odor produces some unique pattern of activation in various glomeruli. Humans have about 6 millions olfactory receptor neurons.
