Physiology

Question 1

what does frequency of sound dictate?

Answer 1

pitch (high or low)

Question 2

what does amplitude of sound dictate

Answer 2

intensity (quiet or loud)

Question 3

what is 0 on an audiogram?

Answer 3

this is the hearing of a healthy 20-year-old male

Question 4

what is considered normal hearing on an audiogram

Answer 4

hearing below 20-25

Question 5

two ways the middle ear changes vibrations in the air to fluid vibrations in the cochlear

Answer 5

1. tympanic membrane to oval window is 18:1

2. malleus handle is much bigger than the incus long process

Question 6

what does the scala media contain?

Answer 6

endolymph

Question 7

what is suspended between scala tympani and scala vestibuli?

Answer 7

scala media

Question 8

what does the scala tympani and scala vestibuli contain?

Answer 8

perilymph

Question 9

what does the frequency of sound vibrate in the cochlea?

Answer 9

different parts of the basilar membrane that hold hair cells (tonotopic organisation of the cochlea)

Question 10

describe tonotopic organisation of the cochlea

Answer 10

high frequencies at the base

low frequencies at the apex

Question 11

difference between inner and outer hair cells

Answer 11

inner hair cells sense sound

outer hair cells have a modulating effect (switch cochlea on and off)

Question 12

pathway of the AP from hair cells to the brainstem

Answer 12

ECOLI
eighth cranial nerve
cochlear nucleus
superior olivary complex
lateral lemniscus
inferior colliculus

Question 13

where is sound perceived in the brain?

Answer 13

primary auditory cortex in left posterior superior temporal gyrus (Brodman areas 41/42) found in the temporal lobe

Question 14

what opens the eustachian tube?

Answer 14

tensor veli palatini

levator palatine

Question 15

what does dysfunction of opening the eustachian tube lead to?

Answer 15

negative middle ear pressure

Question 16

what week in-utero can the foetus hear?

Answer 16

18 weeks

Question 17

how many weeks when the foetus will respond to sound/voice

Answer 17

26 weeks

Question 18

hearing is fundamental for speech development (milestones)

Answer 18

3 months recognises mothers voice

6 months turns to sound

Question 19

input systems into balance

Answer 19

visual
cardiovascular (perfuses the systems involved with balance)
proprioceptive
vestibular

Question 20

output systems of balance

Answer 20

vestibulopsinal tract

vestibulo-ocular reflex

Question 21

vestibular end organs

Answer 21

SVN: lateral and anterior SCC and utricle
IVN: posterior semi-circular canal and saccule

Question 22

two types of hair cells

Answer 22

kinocilium

stereocilia

Question 23

what are the otolith organs

Answer 23

utricle

saccule

Question 24

what do the utricle and saccule contain?

Answer 24

macules containing stereocilia projecting upwards into a gelatinous matrix with otoconia

Question 25

describe the vestibular-ocular reflex

Answer 25

brain perceives position and movement when tilting head/linear motion

Question 26

what are the receptors for taste and smell?

Answer 26

chemoreceptors

Question 27

what do taste buds consist of?

Answer 27

sensory receptor cells and support cells arranged like orange segments

Question 28

what are taste cell receptors replaced by?

Answer 28

basal cells

Question 29

four types of papillae in the human tongue

Answer 29

filiform= most numerous but do not contain taste buds | fungiform, vallate and foliate all contain taste buds

Question 30

describe the pathway of taste

Answer 30

- binding of chemicals to receptor cell alters ionic channels producing a depolarising AP - afferent nerve fibres synapse with receptor cells - signals are sent to cortical gustatory areas

Question 31

ways afferent taste fibres reach the brainstem

Answer 31

``` CNVII= chorda tympani CNIX= supplies posterior 1/3rd of tongue CNX= epiglottitis and pharynx ```

Question 32

five primary tastes

Answer 32

1. bitter= stimulated by alkaloids, poison 2. sour= acids containing free H+ 3. salt= NaCl 4. sweet= stimulated by glucose 5. umami (meat or savoury) triggered by amino acids

Question 33

abnormalities of taste

Answer 33

ageusia hypogeusia dysgeusia

Question 34

where is the olfactory mucosa located?

Answer 34

dorsal roof of the nasal cavity

Question 35

what does the olfactory mucosa contain?

Answer 35

olfactory receptor cells supporting cells basal cells (secrete mucus)

Question 36

describe the structure of olfactory receptor cells

Answer 36

neurone with a thick dendrite and expanded end called an olfactory rod which cilia project from and cause odorants to bind

Question 37

role of basal cells in the olfactory mucosa

Answer 37

act as precursors for new receptor cells

Question 38

what do afferent fibres of the olfactory nerve pierce?

Answer 38

cribriform plate and enter olfactory bulbs on the interior surface of the brain

Question 39

where does the AP go once in the bulb?

Answer 39

passes along olfactory tracts to reach the temporal lobe and olfactory areas

Question 40

during quiet breathing do odorants reach the olfactory mucosa?

Answer 40

no as this is situated above normal air flow

Question 41

what allows odorants to reach the olfactory mucosa?

Answer 41

sniffing enhances the currant upwards

Question 42

what must an odorant contain to be smelled?

Answer 42

it must be volatile enough | sufficiently water soluble (dissolve in mucous coating olfactory mucosa)

Question 43

abnormalities of smell

Answer 43

anosmia hyposmia dysosmia