Physiology

Question 1

Muscles of the middle ear

Answer 1

Tense, stop vibrating instantly and limit chance for distortion
Elastic - dampening vibrations
Small - vibrations don’t spread

Question 2

Tensor Tympani mm

middle ear

Answer 2

Origin - opening to Eustachian tube
-encased in bony canal adjaced
insertion - fibers pass through anterior wall to handle of malleus
action - draws malleus medially and anteriorly, tensing TM

Question 3

Stapedius mm

middle ear

Answer 3

-smallest muscle in body
origin - bony canal adjacent to facial nerve on posterior wall of tympanic cavity
insertion - fibers up and insert in tendon on head of stapes
action - draws stapes posteriorly

Question 4

Middle ear muscles work together

Answer 4

One pulls malleus forward, one the stapes back - separates ossicular chain
-protects ossicles from intense vibrations at 80dB or higher
Acoustic reflex - combined action of the muscles

Question 5

Ossicles

Answer 5

purpose - to proportionally transmit the movement of the TM to the inner ear
-vibrations hit large surface area of TM and need to get to smaller oval window, energy needs to be concentrated
Oval window pushes against fluid, takes more energy to push fluid than air, energy needs to be concentrated
-ossicles lever-like action achieves this - “step-up function”