Topic 8.6

Question 1

3 modalities of the vestibular system

Answer 1

• gravity
• linear head movement
• head rotation

Question 2

What are the sensory receptors of the vestibular system?

Answer 2

the hair cells

Question 3

What type of cells are the hair cells? (2)

Answer 3

• mechanoreceptors

- modified epithelial cells

Question 4

How many steriocilia are on the hair cells?

Answer 4

50-150

Question 5

Type of filament in kinocilia / stereocilia

Answer 5

kino : microtubule

stero : actin

Question 6

What is the vestibule?

Answer 6

The vestibular portion of the membranous labyrinth of the inner ear

Question 7

5 structures of vestibule

Answer 7

• 2 otolithic organs

- 3 semicircular canals

Question 8

What are the 2 otolithic organs?

Answer 8

utricule and saccule

Question 9

Function of otolithic organs

Answer 9

Detection of gravity and linear head movement

Question 10

What are the otolithic organs filled with?

Answer 10

endolymph

Question 11

What are the dark cells?

Answer 11

Vestibular epithelial cells

Question 12

What is the role of the dark cells?

Answer 12

Secretion of K+ into the endolymph

Question 13

How are the hair cells in the utricular macula?

Answer 13

• horizontally oriented

- point towards the striola

Question 14

How are the hair cells in the saccular macula?

Answer 14

• Vertically oriented

- Point away from the striola

Question 15

What is the macula?

Answer 15

Structure that contains the hair cells and supporting cells

Question 16

What do the stereocilia of the hair cells project into?

Answer 16

Into the gelatinous otolithic membrane

Question 17

What is the otolithic membrane made of?

Answer 17

mass of mucopolysaccharides that has otoliths (CaCO3)

Question 18

What happens when there is mvmt to the otolith membrane?

Answer 18

the inertia of the otoliths causes the membrane to move and deflect the stereocili

Question 19

Afferentation of the otolithic organs

Answer 19

• vestibular nerve (CNVIII)
• scarpa’s ganglion
• type I axon
• ipsylateral vestibular nucleus (midbrain)

Question 20

Efferentation of the otolithic organs

Answer 20

• vestibular nucleus
• type II axon
• scarpa’s ganglion
• vestibular nerve

Question 21

Function of semilunar canals

Answer 21

detect head rotation (angular acceleration)

Question 22

What is the sensory region of the semilunar canals?

Answer 22

The ampulla

Question 23

What is the cupula?

Answer 23

mucopolysaccharide gel, without otoliths

Question 24

Main difference between otolith membrane and cupula

Answer 24

the otolith is denser than endolymph but cupula has the same density

Question 25

What is delay of rotation?

Answer 25

When endolymph's acceleration equalizes with the rate of rotation of the semicircular canals

Question 26

Reflexes related to the vestibular system

Answer 26

- vestibulospinal | - vestibulo-ocular

Question 27

What is vestibular nystagmus?

Answer 27

uncontrolled eye movement due to dysfunction of the vestibular labyrinth

Question 28

What are the primary taste qualities? (5)

Answer 28

- bitter - salt - sweet - sour - umami

Question 29

What determines the flavor of a testant?

Answer 29

Both taste and smell

Question 30

What is gustatory disfunction called?

Answer 30

ageusia

Question 31

Where are the taste receptors located?

Answer 31

in the papillae, on the dorsal surface of the tongue

Question 32

3 mechanisms for taste transduction

Answer 32

- tastant passes directly through ion channel (salt) - tastant binds to ion channel (sour) - tastant binds to membrane receptors that open channels (sweet, bitter, umami)

Question 33

Which ion and channel for salt tasting?

Answer 33

- Na+ | - ENaC

Question 34

Which ion and channel for sour taste?

Answer 34

- H+ | - TRPP3

Question 35

Which molecule and receptor for bitter taste?

Answer 35

- toxins | - TAS2R

Question 36

Which molecule and receptor for sweet taste?

Answer 36

- sugar | - TAS1R2 + TAS1R3 dimer

Question 37

Which molecule and receptor for umami taste?

Answer 37

- Amino acids | - TAS1R1 + TAS1R3 dimer

Question 38

What type of protein is gasducin?

Answer 38

Gq type protein

Question 39

Which cranial nerves relay taste information?

Answer 39

- CN VII - CN IX - CN X

Question 40

Which brain structures process taste information? (3)

Answer 40

- anterior insula - frontal operculim - postcentral gyrus

Question 41

What type of cells are the olfactory receptors?

Answer 41

bipolar neurons

Question 42

What is the olfactory epithelium made of?

Answer 42

- olfactory receptor cells - support cells (kinda like glia) - basal cells

Question 43

What is the role of the odorant binding proteins?

Answer 43

help facilitate the diffusion of odorants in the mucus

Question 44

What is the odorant receptor coupled to?

Answer 44

golf protein, Gs type protein

Question 45

What does cAMP bind to in olfactory transduction?

Answer 45

cAMP gated cation channel

Question 46

What does [Ca] increase lead to in olfactory transduction?

Answer 46

opening of Ca activated Cl- channels (outwards)

Question 47

What is a big difference of the olfactory pathway compared to other pathways?

Answer 47

it does not have an obligatory synaptic relay in the thalamus

Question 48

Where is the initial synapse of the olfactory pathway located?

Answer 48

in the olfactory bulb

Question 49

3 structures in the olfactory bulb

Answer 49

- mitral cells - inhibitory interneurons : granule cell, periglomerular cell - glomeruli

Question 50

Role of the granule cells

Answer 50

Form dendrodentritic reciprocal synapses with the mitral cells to enhance stimulus contrast and provide adaptation mechanism

Question 51

Where do the axons of the mitral cells go to?

Answer 51

Anterior olfactory nucleus

Question 52

Where does the lateral olfactory stria go?

Answer 52

primary olfactory striae

Question 53

Where does the medial olfactory stria go?

Answer 53

To the amygdala