olfaction

Question 1

odor

Answer 1

any smell sensation

Question 2

odorant

Answer 2

a chemical compound that we can smell
- it must be volatile, small and hydrophobic

Question 3

nose function

Answer 3

1. filter and hummidify air
2. smell

Question 4

olfactory cleft

Answer 4

part at the back of the nose where the main olfactory epithelium is located

Question 5

olfactory epithelium

Answer 5

patch of tissue in the upper nose that contains ORNs and is covered in a layer of mucus

Question 6

cribiform plate

Answer 6

a bony tructure riddled with tiny holes that separates the nose from the brain
- axons of the ORNs pass through it

Question 7

anosmia

Answer 7

the total inability to smell often resulting from illness or head injuries
- loss of taste

Question 8

supporting cells

Answer 8

metabolic and physcial support to the olfactory receptors

Question 8

cells in the olfactory epithelium

Answer 8

1. supporting cells
2. basal cells
3. olfactory receptor neurons

Question 8

basal cells

Answer 8

precursor cells to olfactory receptor neurons
- help replace them when they die

Question 9

olfactory receptor neurons

Answer 9

the main cell type that contains receptors on its ilia
- located under the watery mucous layer

Question 10

olfactory bulb

Answer 10

bulbous end of the olfactory tract containing mitral, tufted and glomeruli cells

Question 11

mitral cells

Answer 11

the main projective output neurons in the olfactory bulbs
- relay

Question 12

tufted cells

Answer 12

sencodary output neurons in the olfactory bulbs
- their axons form the olfactory tract which go to the brain

Question 13

glomeruli

Answer 13

spherical conglomerates containing the incoming axons of the ORNS
- each receptor cells converge onto two glomureli and then synapse onto the mitral and tufted cells

Question 14

cilia

Answer 14

hair like prootrusions on the dendrites of ORNs that contain receptors for oderants

Question 15

olfactory receptors

Answer 15

region on the cilia that oderant molecules bind to

Question 16

ORN adaptation

Answer 16

the nose adapts to oderants so if ypu give a burst then another immediately after, they will respond less to the second one
- if you wait 5 seconds it will be recovered
- cortical adaptations happens too

Question 17

psuedogenes

Answer 17

we have about 1000 different genes but about 60-70% dont work.
- so we have about 300-400 receptors

Question 18

neural coding for odors

Answer 18

the receptors each bind to one specific molecule but they work together in a population code to to account for the whole variety of smells we perceive

Question 19

piriform cortex

Answer 19

the primary olfactory cortex which receives signals directly from the olfactory bulb
- dedicated solely to olfaction

Question 20

entorhinal cortex

Answer 20

receives direct input from olfactory regions and provides the major association input into the hippocampus

Question 21

amygdala-hippocampus complex

Answer 21

critical for the unique emotional associative properties of olfactory cognition

Question 22

limbic system

Answer 22

the encompassing group of neural structures that include the olfactory cortex, amygdala, hippocampus, piriform cortex and entorhinal cortex
- olfaction is very connected to this system which gives it unique emotional associations

Question 23

tip of the nose phenomenon

Answer 23

• when you know a smell but cat name it
• olfaxtion is disconnected from language and does not fo through the thalamus so it does not integrate with the other senses

Question 24

cross adaptation of smell

Answer 24

the reduction in detection of an oderant following exposure to another oderant

Question 25

cognitive habituation

Answer 25

psychologucal process by which, after a long term exposure to an odorant, one is no longer able to detect that odorant or has very diminished ability

Question 26

why do we have cognitive habituation of smell

Answer 26

1. receptors may be hindered after continuous exposure and may take longer to recycle
2. odorant molecules may be absorbed into bloodstream
3. cognitive-emotional factors

Question 27

attention and smell

Answer 27

we need some level of attention to smell
- looking for smell helps us detect it