The chemical senses

Question 1

What does the olfactory system detect?

Answer 1

Specific molecules: odorants

Question 2

What are odorants

Answer 2

• very volatile and light molecules
• lipid soluble
• mostly organic in origin

Question 3

What are odorant receptors?

Answer 3

• the molecule that transduce odorants into a change in membrane potential

Question 3

What type of receptors are odorant receptors?

Answer 3

• metabotropic g-protein coupled receptors

Question 4

What is the olfactory epithelium?

Answer 4

• tissue in the nasal sinus
• contains olfactory receptor cells

Question 5

How many types of olfactory receptor proteins does an olfactory receptor cell express?

Answer 5

one type

Question 6

How many types of odorant receptors do humans have?

Answer 6

400

Question 7

How can humans detect so many different odors?

Answer 7

through combinatory activation

Question 8

What determines if we like or dislike an odor?

Answer 8

only learned association, nothing else

Question 9

What is the particularity of olfactory information?

Answer 9

Only sensory information that is not relayed in the thalamus

Question 10

What is the transit of olfactory information?

Answer 10

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

Question 11

What are glomeruli?

Answer 11

regions in the olfactory bulb that are highly specialized and receive information from only one specific type of olfactory receptor cell at once

Question 12

What are pheromones?

Answer 12

molecules released by one animal to signal something to another member of the same species

Question 13

How is the response to pheromones determined?

Answer 13

it is entirely innate

Question 14

What are some of the uses of pheromones?

Answer 14

• attract/repel members of the same species
• signal attractiveness
• signal sexual receptivity
• mark a path to follow
• signal danger

Question 15

Where does the initial transduction and processing of pheromones occur?

Answer 15

• in the vomeronasal organ and the accessory olfactory bulb

Question 16

Where is the vomeronasal organ situated?

Answer 16

-next to the regular olfactory epithelium

Question 17

What type of receptors detect pheromones?

Answer 17

• metabotropic vomeronasal receptors

Question 18

How are pheromones released?

Answer 18

through urine

Question 19

How are pheromones sensed?

Answer 19

by being actively sniffed or tasted

Question 20

What type of pheromone signaling is the most powerful?

Answer 20

female to male

Question 21

How does pheromone release and perception influence the sexual behaviors of male rodents?

Answer 21

• 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

Question 22

What is the influence of pheromones on the preference of female rodents for certain male rodents?

Answer 22

female rodents prefer male rodents that have healthy testosterone levels, presumably because of testosterone-induced male sex pheromone signaling

Question 23

What is the lee-boot effect?

Answer 23

When female mice are housed without males (without male pheromones) their estrous cycles slow down and stop

Question 24

What is the Whitten effect?

Answer 24

Pheromones in the urine of male mice can trigger synchronous estrus cycles in groups of female mice

Question 25

What is the Vandenburgh effect?

Answer 25

Female animals that are housed with males will have an earlier onset of puberty

Question 26

What is the Bruce effect?

Answer 26

Female rodents have a tendency to terminate pregnancy following exposure to the scent of an unfamiliar male

Question 27

What is particular about the urine of castrated males?

Answer 27

does not produce any male-to-female pheromone effects

Question 28

What is male pheromone production dependent on?

Answer 28

testosterone

Question 29

What are the male-to-female pheromone effects?

Answer 29

Lee-Boot effect
Whitten effect
Vandenburg effect
Bruce effect