The chemical senses Flashcards
What does the olfactory system detect?
Specific molecules: odorants
What are odorants
- very volatile and light molecules
- lipid soluble
- mostly organic in origin
What are odorant receptors?
- the molecule that transduce odorants into a change in membrane potential
What type of receptors are odorant receptors?
- metabotropic g-protein coupled receptors
What is the olfactory epithelium?
- tissue in the nasal sinus
- contains olfactory receptor cells
How many types of olfactory receptor proteins does an olfactory receptor cell express?
one type
How many types of odorant receptors do humans have?
400
How can humans detect so many different odors?
through combinatory activation
What determines if we like or dislike an odor?
only learned association, nothing else
What is the particularity of olfactory information?
Only sensory information that is not relayed in the thalamus
What is the transit of olfactory information?
1) olfactory receptor senses an odorant
2) action potential is sent down the axon
3) synapses in the glomeruli of the olfactory bulb
4) the golmeruli perceived the NTs emitted by the axons of the olfactory receptors
5) an action potential is sent down the axons of the cells in the glomeruli accordingly
6) the information is sent directly to the primary olfactory cortex and the amygdala
What are glomeruli?
regions in the olfactory bulb that are highly specialized and receive information from only one specific type of olfactory receptor cell at once
What are pheromones?
molecules released by one animal to signal something to another member of the same species
How is the response to pheromones determined?
it is entirely innate
What are some of the uses of pheromones?
- attract/repel members of the same species
- signal attractiveness
- signal sexual receptivity
- mark a path to follow
- signal danger
Where does the initial transduction and processing of pheromones occur?
- in the vomeronasal organ and the accessory olfactory bulb
Where is the vomeronasal organ situated?
-next to the regular olfactory epithelium
What type of receptors detect pheromones?
- metabotropic vomeronasal receptors
How are pheromones released?
through urine
How are pheromones sensed?
by being actively sniffed or tasted
What type of pheromone signaling is the most powerful?
female to male
How does pheromone release and perception influence the sexual behaviors of male rodents?
- male mice who have functional vomeronasal systems will only attempt to mate with females in heat
- male mice with non functional vomeronasal systems will attempt to mate with any mouse
What is the influence of pheromones on the preference of female rodents for certain male rodents?
female rodents prefer male rodents that have healthy testosterone levels, presumably because of testosterone-induced male sex pheromone signaling
What is the lee-boot effect?
When female mice are housed without males (without male pheromones) their estrous cycles slow down and stop
