The Ear

Question 1

What are the three divisions of the ear

Answer 1

External, middle and internal

Question 2

What is the external ear composed of

Answer 2

The auricle, external auditory meatus and the external surface of the tympanic membrane

Question 3

What is the middle ear composed of

Answer 3

The internal surface of the tympanic membrane, tympanic cavity, ossicles and pharyngotympanic tube

Question 4

What is the internal ear composed of

Answer 4

Auditory meatus, vestibular apparatus, internal auditory meatus, vestibulocochlear nerve, oval window and round window

Question 5

What is the auricle composed of

Answer 5

Elastic cartilage

Question 6

What controls the auricle

Answer 6

Muscles of facial expression

Question 7

Where does lymph from the auricle drain to

Answer 7

The parotid and cervical lymph nodes

Question 8

What supplies the auricle with blood

Answer 8

Superficial temporal, anterior auricular, posterior auricular and perforating branches

Question 9

What innervates the auricle

Answer 9

CN V3, CN XI, CN VII and the lesser occipital and greater auricular nerves from the cervical plexus

Question 10

What is the external auditory meatus composed of

Answer 10

Lateral 1/3rd - elastic cartilage, hair follicles, sweat and sebaceous glands
Middle 2/3rd - bone lined with stratified squamous epithelium

Question 11

Blood supply of the external auditory meatus

Answer 11

Auricular branch of the external carotid

Question 12

Innervation of the external auditory meatus

Answer 12

Mainly from the auriculo-temporal from CN V2 but also supplied by auricular branch from CN VII and CN X

Question 13

What is the outer surface of the tympanic membrane covered by

Answer 13

Stratified squamous epithelium

Question 14

What is the inner surface of the tympanic membrane covered by

Answer 14

Mucous membrane

Question 15

Where is the chorda tympani found

Answer 15

On the medial surface of the tympanic membrane

Question 16

What attaches to the inner surface of the tympanic membrane

Answer 16

The malleus

Question 17

What innervates the lateral surface of the tympanic membrane

Answer 17

Tympanic branches of the glossopharyngeal nerve

Question 18

What is the combined action of tensor tympani and stapedius

Answer 18

To reduce the vibrations passing to the delicate inner ear

Question 19

What supplies the tympanic cavity with sensory innervation

Answer 19

CN XI

Question 20

What provides the tympanic cavity with blood

Answer 20

Mostly from tympanic branches of the posterior auricular, ascending pharyngeal and maxillary arteries

Question 21

How does the chorda tympani leave the tympanic cavity

Answer 21

Via the petrotympanic fissue

Question 22

What does the chorda tympani join

Answer 22

The lingual nerve

Question 23

What does the chorda tympani provide

Answer 23

Parasympathetic innervation to the sublingual and submandibular salivary glands and special taste to the anterior 2/3rd of the tongue

Question 24

What does the auditory tube connect

Answer 24

The nasopharynx with the tympanic cavity

Question 25

What is the lateral section of the auditory tube composed of

Answer 25

A bony canal lined with mucosa

Question 26

What is the medial section of the auditory tube compose of

Answer 26

Cartilaginous and membranous tubes

Question 27

What opens the lumen of the auditory tube

Answer 27

The contraction of tensor veli palatini

Question 28

What does the opening of the auditory tube cause

Answer 28

Equalisation of pressure on both sides of the tympanic membrane

Question 29

What innervates the auditory tube

Answer 29

Provided sensory innervation via CN XI

Question 30

What provides blood to the middle ear

Answer 30

Mainly from the anterior tympanic but also from ascending pharyngeal, middle meningeal, posterior auricular, artery of the pytergoid canal and caroticotympanic branch of the internal carotid

Question 31

What is within the inner ear

Answer 31

Bony and membranous labyrinths

Question 32

What are membranous labyrinths

Answer 32

A continuous system of ducts and sacs within the bony labyrinth

Question 33

What are the membranous labyrinths suspended in

Answer 33

Perilymph

Question 34

What is contained within the membranous labyrinths

Answer 34

Endolymph

Question 35

Function of endolymph and perilymph

Answer 35

Conduction of sound vibrations and respond to mechanical forces

Question 36

What are the parts of the semicircular canals

Answer 36

Anterior, posterior and lateral

Question 37

Arrangement of the parts of the semicircular canals

Answer 37

The anterior and posterior are at 90 degrees and the lateral is horizontal

Question 38

What is within the semicircular canals

Answer 38

Semicircular ducts

Question 39

What are the semicircular ducts continuous with

Answer 39

The ampulla

Question 40

What is the ampulla

Answer 40

A swelling at the end of a duct

Question 41

What is within the ampulla

Answer 41

The crista ampullaris

Question 42

Function of the crista ampullaris

Answer 42

Responds to angular movements of the head

Question 43

What is within the vestibule

Answer 43

The utricle and saccule

Question 44

What is within the utricle and saccule

Answer 44

Equilibrium receptors known as maculae

Question 45

Function of the maculae

Answer 45

Respond to the pull of gravity and changes in head position

Question 46

What supplies the inner ear with blood

Answer 46

Main supply from the internal auditory

Question 47

What are the branches of the internal auditory artery

Answer 47

Common vestibular and cochlear arteries

Question 48

What is the internal auditory artery usually a branch of

Answer 48

Anterioinferior cerebellar or the basilar arteries