Hearing and Balance Wk6

Question 1

What are the 2 types of hearing loss?

Answer 1

Conductive - outer/middle
Sensorineural - inner ear/auditory nerve

Question 2

Tympanic membrane

Answer 2

*Transduces pressure waves (sonic vibrations)
into mechanical vibration
*Innervation: CN V, CN VII, CN IX

Question 3

Middle ear has 3

Answer 3

ossicles - malleus, incus, stapes

Question 4

Inner ear lies in the

Answer 4

petrous part of the temporal bone

Question 5

What is located in the cochlear

Answer 5

Auditory sensory receptors - hair cells

Question 6

In the cochlear what are the 2 membranes?

Answer 6

Reissner’s (vestibular)
Basilar

Question 7

In the cochlear, what is the 3 compartments?

Answer 7

Scala vestibuli
Scala media
Scala tympani

Question 8

What does the scala tympani and vestibuli contain?

Answer 8

Perilymph (VT = P)

Question 9

What does the scala media contain?

Answer 9

Endolymph (ME)

Question 10

What does the organ of corti do?

Answer 10

detection and amplification of sound

Question 11

What is mechanotransduction?

Answer 11

Ability of a cell to actively sense, integrate, and convert mechanical stimuli into biochemical signals that result in intracellular changes, such as ion concentrations, activation of signaling pathways and transcriptional regulation

Question 12

Explain the process of mechanotransduction

Answer 12

Up/Down movement of basiliar membrane deflects hair cell stereocilia
- BM mmt up

Question 13

• BM mmt up

Answer 13

depolarises/activates inner hail cells

Question 14

BM mmt down

Answer 14

hyperpolarises/inhibits inner hair cells

Question 15

Where does the signal get transmitted to?

Answer 15

Signal transmitted to CNS via vestibulocochlear (CN VIIIth) nerve

Question 16

What nerve carries the heraring and balance?

Answer 16

Vestibulocochlear nerve - 8th nerve

Question 17

What is the vestibular system composed of?

Answer 17

Peripheral vestibular system (sensory organs -> inner -> hair cells), and central vest system - brainstem nuclei

Question 18

Utricle

Answer 18

Detects linear acceleration in horizontal plane

Question 19

Saccule

Answer 19

Detects linear acceleration in vertical plane
and gravity

Question 20

Describe how perturbations activate vestibulospinal reflexes to maintain posture and balance

Answer 20

Medial VST, Lateral VST

MVST:
As far as cervical region
Vestibulo-collic reflexes also
Innervate - Anti-gravity extensors

Question 21

Explain how head movement results in
compensatory eye movements – horizontal
VOR

Question 22

Mmt TOWARD kinocilium

Answer 22

Excites hair cell

Question 23

Mmt AWAY from kinocilium

Answer 23

Inhibits hair cells