OS III, Ex II, smell

Question 1

What is the olfactory nerve?

Answer 1

Cranial nerve 1

Question 2

what type of receptor cells form the nerves that project into CN !

Answer 2

Bipolar receptor cells

Question 3

what type of materials can activate receptors?

Answer 3

Mucous soluble materials

Question 4

what has odarent receptors?

Answer 4

cilia that project into nasal mucous

Question 5

life span of olfactory receptors?

Answer 5

1 - 2 months

Question 6

How are olfactory receptors replaced?

Answer 6

basal stem cells.

Question 7

Why can elderly people not smell well?

Answer 7

overall number of receptor cells decrease with age

Question 8

what do mucous soluble odarants activate?

Answer 8

Na/Ca and Cl ion channels on receptor microvilli

Question 9

Activation of the ion channels, Na/Ca, Cl does what

Answer 9

depolarization and AP generation

Question 10

what is sensory adaptation?

Answer 10

cant smell something after prolonged exposure

Question 11

what causes sensory adaptation?

Answer 11

Ca+ independent and dependent paths that inhibit receptors, close ion channels and remove ions that have got in

Question 12

How many types of odarant receptors does human have?

Answer 12

300 types of odarante receptor, but only one per receptor

Question 13

What cell type does the bipolar receptor cells innervate in olfactory bulb?

Answer 13

mitral cells, this is on the top side of cribiform plate

Question 14

What converge onto individual mitral cells?

Answer 14

axons with similar inputs(smells/receptor type) in groups of 10-100

Question 15

what is a mitral cell?

Answer 15

what the odarant cells innervate with in the olfactory bulb

Question 16

where does olfactory bulb project to?

Answer 16

piriform cortex on the medial surface of the temporal lobe

Question 17

Where does the piriform cortex project olfactory info to?

Answer 17

amygdala, hippocampus and prefrontal cortex

Question 18

What are the characteristics of the primitive piriform cortex? 3

Answer 18

Conciousness of odors, singularity, habituation

Question 19

What does piriform cortex neurons respond to?

Answer 19

odarent mixtures not components

Question 20

what makes olfactory conscious experient different from vision and audition?

Answer 20

the experience is usually singular with one odar event at a time

Question 21

what is it rare for someone to be able to do?

Answer 21

recal mental images of odars, or to detect more than one component at a time

Question 22

What is habituation?

Answer 22

reduced cortical restponse to continuted chemical stimulation

Question 23

What are the two reasons we can smell the same odor for a prolonged time?

Answer 23

Habituation - reduced cortical response and, receptor ataptiation - Ca dep/indep responses at olfactory epithelium

Question 24

what is the point of habituation?

Answer 24

to detect new odarants against background of current odars.

Question 25

What does amygdala have to do with olfaction

Answer 25

Amygdala is for generating emotion and associatave learining, smell goes through here, that is why a certain scent can bring back such strong memories.

Question 26

what sensations can bring back the strongest emotions

Answer 26

smell is greater than both vision and autitory cues

Question 27

what does the following scents do?

Answer 27

citrus - improve psychological states and immune function of those with depression, rose - inhibit stress induced skin barrier distruption, orange and laventer - reduce anxiety of patients.

Question 28

where does the piriform cortex and amygdala project to?

Answer 28

orbitofrontal cortex OFC, a part of the prefrontal cortex

Question 29

what does the orbitofrontal cortex act with?

Answer 29

amygdala in emotion and associative learning

Question 30

what gives us the subjective idea of an odar smelling good or bad?

Answer 30

orbitofrontal cortex, OFC

Question 31

what does the OFC, orbitofrontal cortex associate olfactory with?

Answer 31

Associates smell with taste, oral texture, visual inputs, to give us food reward value

Question 32

What is retronasal olfaction

Answer 32

how taste interacts with smell

Question 33

what is valuation of smell from OFC inportaint for?

Answer 33

emotion, and in autonomic responses such as heart rate, skin conductances responses mediated by amygdala

Question 34

what is one draw back to olfacton?

Answer 34

the receptors come in direct close contact with brain allowing spread of pathogens

Question 35

how do viruses get to olfactory bulb?

Answer 35

they travel along axons, then across synaps to limbic system

Question 36

How do bacteria get to olfactory bulb?

Answer 36

penetrate olfactory mucosa cells, then transported into the subarachnoid space leading to meningitus

Question 37

what is intranasal infusion?

Answer 37

a way for medications to be delivered to CNS through the nasal mucosa, bypassing the BBB. Insulin can do this.

Question 38

What is another pathway to get from nasal mucosa to CNS

Answer 38

through the trigenimal nerve pathway.