physiology-ear

Question 1

what dictates the pitch of a sound?

Answer 1

frequency

Question 2

what dictates the intensity of a sound?

Answer 2

amplitude

Question 3

what frequency can humans hear?

Answer 3

20Hz-20,000Hz

Question 4

what graph can be used to cover hearing range?

Answer 4

audiogram

Question 5

what do the ‘O’ and ‘X’ represent in an audiogram?

Answer 5

o= right ear air conduction

x=left ear air conduction

Question 6

what allows amplification of sound in the middle ear?

Answer 6

-size of tympanic membrane compared to oval window (18:1)

Question 7

what are the three parts inside the cochlear?

Answer 7

• scala tympani (contains perilymph)
• cochlear duct/ scala media (contains endolymph)
• scala vestibuli (contains perilymph)

Question 8

where are the inner hair cells found in the cochlea?

Answer 8

-in the organ of corti

Question 9

what is the role of the inner hair cells?

Answer 9

-involved in receiving sound and passing the sound up the auditory nerve by turning it into action potential (they sway causing voltage gates to open, causing depolarisation, creating an action potential)

Question 10

what is the role of the outer cells?

Answer 10

-modifying sound

Question 11

where is the primary auditory complex located?

Answer 11

left posterior superior tempoal gyrus (Broadmans area 41/42)

Question 12

what is the role of the eustachian tube?

Answer 12

equalise pressure in ears

Question 13

what is the resting state of the eustachian tube like?

Answer 13

-it is closed but can be opened by tensor veli palatini and levator palatine muscles

Question 14

what role does have external ear have in hearing?

Answer 14

sound collector

Question 15

what role does the middle ear have in hearing?

Answer 15

mechanical force of amplification

Question 16

what role does the inner ear have in hearing?

Answer 16

sound transducer/analyser

Question 17

at what age in the utero can a foetus hear?

Answer 17

18 weeks

Question 18

at what age in the utero can a foetus respond to sound/voice?

Answer 18

26 weeks

Question 19

what system in your ear is responsible for balance?

Answer 19

vestibular system

Question 20

what nerve supplies the lateral, anterior semi-circular canal and utricle?

Answer 20

SVN (superior vestibular nerve)

Question 21

what nerve supplies the posterior semicircular canal and saccule?

Answer 21

-inferior vestibular nerve (IVN)

Question 22

what are the longest hair cell?

Answer 22

kinocilium

Question 23

what are stereocilia?

Answer 23

hair cells that increase in length until the kinocilium (longest hair cell) (found in the semicircular canals)

Question 24

what occurs if there if the stereocilia move towards compared to away from the kinocilium?

Answer 24

towards- increase in action potential

away- decrease in action potential

Question 25

what allows you to percieves position and movement when tilting head or linear motion?

Answer 25

- in the utricle and saccule there is maculae - maculae of these organs have stereocilia projecting upwards into a gelatinous matrix with otoconia (otolith organs) - this means when you move head/tilt it the hair cells drag allowing you to feel motion

Question 26

what occurs to firing rate of hair cells in semicircular ducts as you tilt head left/right horizontally?

Answer 26

left= inhibition so decrease in firing rate | right=excitation so increase in firing rate

Question 27

what allows you to stabilize your gaze?

Answer 27

vestibular ocular reflex

Question 28

what is nystagmus?

Answer 28

-a rhythmical, repetitive and involuntary movement of the eyes

Question 29

what occurs if you have right vestibular damage?

Answer 29

you think youre turning left when you aren't actually | -can cause vertigo

Question 30

what is bi directional nystagmus?

Answer 30

look to left- eye moves fast to left look to right- eye moves fast to right -indicates a central vestibular problem

Question 30

what does communications in vestibular nuclei with outputs to the vestibular tract involve?

Answer 30

- motor output to neck, back and leg muscles | - involves posture

Question 31

what does communications in vestibular nuclei with outputs to the medial longitudinal fasciculus and ocular muscles involve?

Answer 31

motor output to eyes | -gaze stabilisation

Question 32

what does communications in vestibular nuclei with outputs to the medial lemniscus and thalamus to cerebrum involve?

Answer 32

awareness