CNS/sensory 6 - vestibular, olfactory, gustatory

Question 1

where are vestibular organs

Answer 1

located in inner ear

Question 2

what are vestibular organs

Answer 2

all fluid filled compartments
transduction process same as cochlea
tells you how head moves through space

Question 3

describe utricle and saccule

Answer 3

linear acceleration
forwards/backwards, up/down
utricle = horizontal
saccule = vertical

Question 4

describe semicircular canals

Answer 4

encode angular acceleration
as head rotates up and down

Question 5

describe vestibular ocular reflex

Answer 5

balance, helps you understand how head moves but also controls eyes
when wiggle head = activate reflex
as move head in one direction = vestibular signals that detect head acceleration (angular movement) cause your eyes to move in opposite direction = reflex
keeps gaze (what looking at) constant

Question 6

how does transduction occur for vestibular

Answer 6

tip links gate ion channels
only difference = way stereocilia moved

Question 7

describe organization of semicircular canals

Answer 7

ampula = gets big, in fluid structures
cupula = mass of gelatine like membrane, can bend
stereocilia = inside cupula
diff angles encode rotation

Question 8

describe process of semicircular canals

Answer 8

cupula moves since head moves
fluid has inertia so does not move right away = exerts force on cupula and causes it to bend stereocilia = pulls on tiplinks and ion channels open or close

Question 9

describe motion sickness

Answer 9

vestibular system being activated but conflicts with visual system that says we are not moving

Question 10

describe dizziness

Answer 10

spinning in chair = fluid has inertia and lags but then catches up and then you stop and fluid exerts force on cupula and bends stereocilia
so brain says im moving but you just stopped = vebstibualr system still thinks head is moving

Question 11

what do utricle and saccule detect

Answer 11

linear acceleration
similar transduction
fluid filled

Question 12

describe utricle and saccule process

Answer 12

Epithelium layer of hair cells sticks up stereocilia into otoliths (jelly mass with rock)
= float in fluid but when acceleration = otoliths have inertia and do not accelerate right away
once maintain constant speed = otoliths catch up and back to neutral, stereocilia not bent

Question 13

describe what happens alcohol - utricle and saccule

Answer 13

feel dizzy at end of night bc alc changes specific gravuty of fluid in inner ear and otoliths no longer naturally buoyant and starts to float = gives sensation of movement

Question 14

describe taste - gustation

Answer 14

papillae has taste buds, inside grooves of papillae
Saliva dissolves molecules and goes to taste bud then binds inside taste pore (lined with taste cells - bind chemically to receptors and initiates cells)
taste afferent = active and sends ap to brain

Question 15

how many taste buds do we have

Answer 15

10,000 taste buds
but can only distinguish a few tastes

Question 16

describe taste transduction

Answer 16

each taste mediated slightly diff transduction process

Question 17

describe umami transduction

Answer 17

umami –> glutamate receptors on tongue –> g protein cascade = gives umami flavour, flavour enhancement like msg

Question 18

describe salty transduction

Answer 18

due to sodium ions of food in mouth flowing through iron channels selective for sodium

Question 19

describe sour transduction

Answer 19

high acid
extra protons interact with channels = block or enhance them
source can block sodium - tastes interact

Question 20

describe bitter transduction

Answer 20

very complex

many substances = developed as protection mechanism
blocks ion channels (potassium)

or

specialized bitter receptors that bind molecules that taste bitter and then triggers various g protein cascades = open/close/modify ion channels
many transduction processes

Question 21

describe sweet transduction

Answer 21

sugar binds to specialized receptors on taste cell that then active g protein cascade and open /close ion channels

Question 22

Describe central taste pathways

Answer 22

afferent activated and travels to cns by cranial nerves –> synapse in medulla –> thalamus –> projects into gustatory complex to ipsilateral gustatory cortex (does not cross midline), perception of taste happens

Question 23

what is spicy

Answer 23

pain or heat response
not taste

Question 24

describe olfaction

Answer 24

odorant molecules enter nose and nasal cavity
has olfactory epithelium
binds to olfactory receptor cells that have cilia that line top of nasal cavity - sit in layer of mucous, ordorant molecules dissolve in mucous and bind chemically with receptors in cilia
Olfactory receptor cells (send axons across bone) –> olfactory nerve –> olfactory bulb (has circuitry, part of cns) –> axons from olfactory tract foes to other parts of brain

Question 25

Describe olfaction signal transduction

Answer 25

1 - odorant binding to oderant receptors the (weak or strongly)
2 - g protein cascade activation (motors, opens ion channels)
(each taste cell, expresses unique set of odorant receptors - selective to unique chemical composition of odors)
3 - open ion channels

Question 26

how many oderant receptors and describe sensitivity

Answer 26

1000 oderant receptors
Sensitive to 10000 diff odors = satisfaction when eating food mostly comes from smell not taste
some molecules bind some receptors tightly and others less = sets up population code, even tho only 1000 receptors - odorant molecules bind more than on type of receptor

Question 27

describe central olfactory pathways

Answer 27

sent to olfactory bulb = does processing and sends via olfactory tract directly into limbic system
odors and smells can trigger emotions
direct link between olfaction emotions and memory

Question 28

what are emotional responses mediated by

Answer 28

involved in emotions and memory
how we score and rate sensory experiences
tend to remember experiences that produce high emotional response - good or bad

Question 29

describe perfumes

Answer 29

whole industry dedicated to limbic system
how you smell = affects limbic systems of other ppl