1 - Anatomy & Physiology of Middle Ear

Question 0

The Eustachian tube connects the middle ear with the __________.

Answer 0

Nasopharynx

Question 1

What is the middle ear filled with?

Answer 1

Air

Question 2

What is the largest part of the tympanic membrane?

Answer 2

The pars tensa

Question 3

How many parts does the pars tensa have?

Answer 3

3

Question 4

Describe the pars tensa

4

Answer 4

Tense

Vibrates in response to sound

Has a blood supply

Is innervated

Question 5

What is the densest part of the tympanic membrane?

Answer 5

Pars flaccida

Question 6

Which is less tense: the pars tensa or the pars flaccida?

Answer 6

The pars flaccida

Question 7

What is the function of the tympanic membrane?

Answer 7

To transduce sound pressure into mechanical vibrations

Question 8

Name the three ossicles

Answer 8

Malleus

Incus

Stapes

Question 9

What is the extension of the malleus that connects to the tympanic membrane?

Answer 9

Manubrium

Question 10

What is the name of the center of the tympanic membrane where the Manubrium attaches?

Answer 10

Umbo

Question 11

What does the head of the malleus connect to?

Answer 11

The head of the incus

Question 12

What are the two middle ear muscles?

Answer 12

Stapedius muscle

Tensor Tympani

Question 13

What is the smallest human muscle?

Answer 13

Stapedius muscle

Question 14

Where does the stapedius muscle attach?

Answer 14

Attaches to the head of the stapes

Question 15

Where does the tensor tympani muscle attach?

Answer 15

To the upper part of the manubrium

Question 16

To what does the tensor tympani muscle run parallel to?

Answer 16

The Eustachian Tube

Question 17

What is unique about the middle ear muscles?

Answer 17

The are totally encased in bone.

Only their tendons are exposed to attach to the ossicles

Question 18

What is the function of the middle ear muscles?

Answer 18

Act in concert to modify the ossicles’ alignment

Provide protection from loud sounds

Provide amplification for soft sounds

Question 19

What happens to the middle ear muscles during sustained long sounds?

Answer 19

They tense up so that less pressure is being applied to the oval window

Question 20

What is the dynamic range of hearing?

Answer 20

From the threshold of hearing (softest sound you can detect) to the threshold of pain (loudest sound you can comfortably tolerate)

Question 21

How is the impedance imbalance of the inner ear compensated for?

Answer 21

The size of the tympanic membrane vs. the size of the stapedial footplate

The leverage created by the geographic configuration of the ossicles

Question 22

The area of the tympanic membrane vs. the area of the stapedial footplate improves sound transmission by ___________.

Answer 22

25 dB

Question 23

The leverage provided by the ossicles improves sound transmission by __________.

Answer 23

12-13 dB

Question 24

What are the four quadrants of the tympanic membrane?

Answer 24

Posterior Superior Posterior Inferior Anterior Superior Anterior Inferior

Question 25

What are the parts of the middle ear? | 5

Answer 25

Tympanic Membrane Ossicular Chain Tendons Muscles Eustachian Tube

Question 26

What is the name of the groove where the TM is located?

Answer 26

Tympanic Sulcus

Question 27

What are the parts of the tympanic membrane? | 7

Answer 27

Pars Flaccida Pars Tensa Umbo Cone of Light Tympanic Ring Manubrium Notch of Rivinus

Question 28

The ear drums slant towards _________.

Answer 28

The nose

Question 29

What are the three layers of the tympanic membrane?

Answer 29

Cutaneous Fibrous Internal

Question 30

What is the Cutaneous Layer of the TM like?

Answer 30

Outer Layer Composed of same skin that covers last portion of the external ear canal

Question 31

What is the Fibrous Layer of the TM like?

Answer 31

It provides most of the structure, integrity, and compliance Its density is greatest at the center

Question 32

What are the two layers of the TM's Fibrous Layer

Answer 32

Radial Fibers Spiral (Circular) Fibers

Question 33

What is the Internal Layer of the TM like?

Answer 33

A mucous membrane

Question 34

What is the Promontory?

Answer 34

A bony area that is the entrance to the cochlea

Question 35

What holds the ossicular chain in place? | 3

Answer 35

Tympanic Membrane 6 Ligaments Tendons of Tensor Tympani & Stapedius Muscles

Question 36

What's different about the middle ear tendons?

Answer 36

They are more elastic than other tendons in body They produce slower muscle contractions - no sudden contractions

Question 37

When does the Tensor Tympani muscle move?

Answer 37

During swallowing, chewing, and other facial movements

Question 38

When does the Stapedius muscle move?

Answer 38

During loud sounds or right before speaking Its movement is involuntary

Question 39

What is the difference between the tensor tympani muscle and the stapedius muscle?

Answer 39

Tensor Tympani = Bigger muscle, smaller effect Stapedius = Smaller muscle, bigger effect

Question 40

How do the tensor tympani muscle and the stapedius muscle interact together?

Answer 40

The contract in opposite directions to prevent rotation of the ossicular chain

Question 41

What is the function of the tensor tympani muscle and the stapedius muscle?

Answer 41

To modify the vibration of the ossicular chain

Question 42

What are the six ligaments of the middle ear?

Answer 42

Superior malleal ligament Lateral malleal ligament Anterior malleal ligament Superior Incudal Ligament Posterior incudal ligament Annular Ligament

Question 43

What are the two muscles of the Eustachian Tube?

Answer 43

Tensor Veli Palatini (TVP) Levator Veli Palatini (LVP)

Question 44

What is the function of the Eustachian Tube?

Answer 44

To equalize the air pressure in the middle ear with the air pressure of the environment To allow fluids in the middle ear to be drained

Question 45

What is the function of the middle ear?

Answer 45

To compensate for the impedance mismatch between the outer and inner ears It takes more energy to produce a sound wave in the inner ear fluids than the atmosphere where the sound was generated

Question 46

What is impedance?

Answer 46

The sum of all the energy that opposes the transmission of sound

Question 47

How much larger is the TM than the Oval Window?

Answer 47

15x larger

Question 48

What is a conductive loss of hearing?

Answer 48

When a patient is missing or has malfunctioning TM and/or ossicles

Question 49

When the Eustachian Tube's muscles are relaxed, the lumen is?

Answer 49

Closed

Question 50

When the Eustachian Tube's muscles are contracted, the lumen is?

Answer 50

Open

Question 51

What is the Lumen?

Answer 51

The tube part of the Eustachian Tube

Question 52

What hair cells are usually damaged in noise-induced hearing loss?

Answer 52

The outer hair cells