ANATOMY - Ear

Question 1

What are the three main divisions of the ear?

Answer 1

External ear
Middle ear
Inner ear

Question 2

What are the two components of the external ear?

Answer 2

Auricle (pinna)
External acoustic meatus

Question 3

What is the function of the superficial auricularis muscles of the auricle?

Answer 3

Superficial auricularis muscles allow the auricle to be orientated towards and localise sound

Question 4

What is the name of the cartilage which makes up the auricle?

Answer 4

Auricular cartilage

Question 5

What anchors the auricular cartilage of the auricle to the base of the skull?

Answer 5

Annular cartilage

Question 6

What is the tragus?

Answer 6

Tragus is the point where the auricular cartilage meets to form a cone at the base of the auricle

Question 7

On which side of of the auricle do the blood vessels run?

Answer 7

External surface of the auricle

Question 8

What are the borders of the external acoustic meatus?

Answer 8

Tragus to the tympanic membrane

Question 9

Which two gland types are found within the skin lining the external acoustic meatus?

Answer 9

Sebaceous glands
Tubular ceruminous glands

Question 10

What is produced by tubular ceruminous glands?

Answer 10

Wax (cerum)

Question 11

Which four structures are a part of the middle ear?

Answer 11

Tympanic membrane
Tympanic cavity
Auditory ossicles
Auditory tube

Question 12

Which structure divides the external acoustic meatus from the middle ear?

Answer 12

Tympanic membrane

Question 13

What lines the external surface of the tympanic membrane?

Answer 13

Epithelium

Question 14

What lines the internal surface of the tympanic membrane?

Answer 14

Mucosa

Question 15

Which skull bone is the tympanic cavity embedded in?

Answer 15

The tympanic cavity is embedded in the temporal bone

Question 16

What are the dorsal and ventral divisions of the tympanic cavity?

Answer 16

Dorsal: Epitympanic recess
Ventral: Tympanic bulla

Question 17

(T/F) The tympanic bulla consists of fluid in a healthy animal

Answer 17

FALSE. The tympanic bulla consists of air in a healthy animal

Question 18

What are the three auditory ossicles?

Answer 18

Malleus
Incus
Stapes

Question 19

Which auditory ossicle is attached to the medial surface of the tympanic membrane?

Answer 19

Malleus

Question 20

What are the two muscles associated with the auditory ossicles?

Answer 20

Tensor tympani
Stapedius

Question 21

What is the function of the muscles associated with the auditory ossicles?

Answer 21

Contraction of the tensor tympani and stapedius muscles reduces the ability of the ossicles to vibrate and thus reduces the amplitude of sound waves

Question 22

What are the two functions of the auditory tube?

Answer 22

Drains fluid secreted by the tympanic membrane into the nasopharynx
Equalises air pressure in the middle ear

Question 23

How does the auditory tube equalise pressure in the middle ear?

Answer 23

The auditory tube connects the middle ear to the nasopharynx and is usually collapsed but during swallowing and yawning, the tube is opened to small amounts or air, allowing for the equalisation if air pressure between the environment and the middle ear

Question 24

What is the outpouching of the auditory tube seen in horses?

Answer 24

Guttural pouch

Question 25

What are the dorsal and ventral openings of the middle ear into the inner ear?

Answer 25

Dorsal: Vestibular window (oval window) Ventral: Cochlear window (round window)

Question 26

Which skull bone completely encloses the inner ear?

Answer 26

Petrous temporal bone

Question 27

What are the two labyrinths found in the inner ear?

Answer 27

Osseous labyrinth Membranous labyrinth

Question 28

What fluid is found between the osseous and membranous labyrinth?

Answer 28

Perilymph

Question 29

What fluid is found within the membranous labyrinth?

Answer 29

Endolymph

Question 30

What are the two central cavities of the membranous labyrinth?

Answer 30

Utriculus Sacculus

Question 31

Which three ducts extend from the utriculus in the membranous labyrinth?

Answer 31

Anterior semicircular duct Posterior semicircular duct Lateral semicircular duct

Question 32

What is the name of the enlargements at the base of the semicircular ducts?

Answer 32

Ampullae

Question 33

Which duct extends from the sacculus in the membranous labyrinth?

Answer 33

Cochlear duct

Question 34

What is the central chamber of the osseous labyrinth which contains the utriculus and sacculus?

Answer 34

Vestibule

Question 35

Which structures of the osseous labyrinth contain the semicircular ducts?

Answer 35

Semicircular canals

Question 36

Which structure of the osseous labyrinth contains the cochlear duct?

Answer 36

Cochlea

Question 37

What is the central, conical shaped structure in the cochlea?

Answer 37

Modiolus

Question 38

Which structure projects from the modiolus of the cochlea?

Answer 38

Spiral lamina

Question 39

What are the three fluid-filled channels within the cochlea?

Answer 39

Scala vestibuli Cochlear duct Scala tympani

Question 40

Which structure separates the scala vestibuli from the cochlear duct?

Answer 40

Vestibular membrane

Question 41

Which structure is located within the cochlear duct?

Answer 41

Organ of corti

Question 42

Which structure separates the cochlear duct from the scala tympani ?

Answer 42

Basilar membrane

Question 43

Which artery supplies the external ear?

Answer 43

Caudal auricular artery

Question 44

Which artery supplies the middle and internal ear?

Answer 44

Occipital artery

Question 45

Which artery do the caudal auricular artery and the occipital artery branch from?

Answer 45

External carotid artery

Question 46

Which vein does the external ear drain into?

Answer 46

Maxillary vein

Question 47

What is an aural haematoma?

Answer 47

A blood filled swelling within the auricle

Question 48

What is the main cranial nerve which innervates the ear?

Answer 48

Cranial nerve VIII (vestibulocochlear nerve)

Question 49

Which nerve innervates the tensor tympani muscle?

Answer 49

Mandibular nerve (branch of CNV)

Question 50

Which nerve innervates the stapedius muscle?

Answer 50

Cranial nerve VII (facial nerve)

Question 51

What is otitis?

Answer 51

Inflammation of the ear

Question 52

What are three methods that can be used to image the ear?

Answer 52

Radiography Advanced imaging Otoscope