Auditory and Vestibular Physiology

Question 1

Function of outer, middle and inner ear

Answer 1

Outer - Collect sound waves and direct them to our ear canal

Middle - ossicles, tympanic membrane for hearing

Inner - Labryrinth for hearing and equilibrium

Question 2

How is pressure in the ear equalised ?

Answer 2

Eustachian tube - connects to naso-pharynx.

Closed, unless opened by pressure. ‘Popping your ears’

Question 3

Describe the process of sound hitting your eardrum to transmitting the vibration to innear ear fluids.

Answer 3

1. Sound in external acoustic meatus (ear canal) hits tympanic membrane and causes vibration
2. Tympanic membrane moves ossicles in middle ear (malleus, incus and stapes)
3. Ossicles articulate to form lever system that amplifies and transmits vibration to fluids of inner ear via oval window

Question 4

What is the tympanic reflex?

Answer 4

Stapedius and tensor tympani muscles are attached to stapes and malleus.

Loud sounds causes the muscles to contract, dampening vibration to lower the noise - tympanic reflex.

Question 5

What fluids can be found in the inner ear’s membranous labyrinth?

Answer 5

Membranous labyrinth filled with endolymph - similar to ICF, high in K+

Labyrinth floats in perilymph - similar to CSF