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Flashcards in Ear anatomy Deck (46):
1

What is the function of the auricle?

 

Collect, focus, and direct sound down the funnel-shaped external acoustic meatus to the tympanic membrane

2

What antibodies have been identified in cerumen?

IgA, IgG and IgM

3

What is the predominant immunoglobulin in normal and inflamed ears?

IgG for both

4

What is the function of the Eustachian (auditory) tube?

Equalize pressure on both sides of the tympanic membrane

5

Name the 2 structures that attach to the malleus

Tympanic membrane and incus

6

Name the 3 components of the middle ear

Tympanic cavity, 3 auditory ossicles and tympanic membrane

7

What 2 structures attach to the stapes?

Vestibular window (in contact with perilymph fluid) and incus

8

Where does the tensor tympani muscle insert?

Malleus

9

What nerve innervates the tensor tympani muscle?

Branch of trigeminal nerve

10

Where does stapedius muscle insert?

Stapes

11

What nerve innervates the stapedius muscle?

Stapedial branch of facial nerve

12

Where do both the tensor tympani and stapedius muscles originate?

Tympanic bulla

13

Name the bony structure that houses the cochea

Promontory (where cochlear and vestibular windows are located)

14

Describe the 3 layers of the tympanic membrane and their origin

Inner epithelium: originates from pharyngeal pouch

Central layer: fibrous connective tissue of pharyngeal wall

Outer layer: stratified squamous epithelium derived from ectoderm of first pharyngeal groove

15

What is the stria mallearis?

Outline of the manibrium of malleus

16

Where should a myringotomy be performed?

Caudal ventral quadrant of TM (pars tensa)

17

Which direction does the manubrium of the malleus face?

C-shaped and concave aspect of the C points rostrally

18

Where and in what direction does tympanic membrane regenerate?

Radially from the umbo pars tensa

 

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19

Name the clinical signs of Horner's syndrome

Ptosis, pupillary miosis, prominent third eyelid, enopthalmia

 

 

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20

Where does the annular cartilage insert?

Within the bone of external acoustic meatus

21

What are the 3 parts of the tympanic cavity?

Dorsal: smallest

Middle (aka tympanic cavity proper): adjacent to TM

Ventral: largest; tympanic bulla with septum bulla

22

Know how to label this

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23

What are the 2 divisions of the septum bulla in cats?

Pars tympanica: small and dorsolateral

Pars endotympanica: large and ventromedial

24

Name another dog breed reported to have PSOM other than CKCS?

Boxer, dachshund, and shih tzu

25

Name the anatomical region where one inserts the ototscopic cone?

Antitragus

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26

What dog breed typically have excessive compound hair follicles in the horizontal ear canal?

Cocker spaniel dogs

27

What dog breeds have simple hair follicles in the horizontal ear canals?

Greyhounds and mixed breed dogs

28

What are simple coiled tubular glands that resemble apocrine sweat glands?

Ceruminous glands

29

Ceruminous glands are composed of an inner secretory layer surrounded by ______ cells on a basement membrane

Myoepithelial cells

30

What is the normal pH of ear canal epithelium in dogs?

A. 4.6-7.2

B. 6.0-7.4

C. 5.2-7.2

D. None of the above

A. 4.6-7.2 -- Normal

B. 6.0-7.4 -- Chronic otitis

C. 5.2-7.2 -- Acute otitis

31

What is the gas in the middle ear composed of?

Nitrogen 83%, oxygen 12%, carbon dioxide 4.7%

32

What is an acoustic reflex?

When the ear is stimulated with a VERY loud sound, the stapedius muscle will contract to protect the middle ear from damaging level of noise

33

Acoustic reflex is usually absent in patients with what disease?

Middle ear disease

34

Blood supply to the ear comes from what 2 main arteries?

External carotid artery and vertebral arteries

35

What is the largest artery to the ear?

Intermediate auricular branch

36

Name the 4 nerves of the sensory innervation of the pinna

Trigeminal, facial, vagus, second cervical

37

Which cartilage does NOT contribute to the formation of the externa ear?

A. Auricular cartilage

B. Annular cartilage

C. Scutiform cartilage

D. None of the above

C. Scutiform cartilage

38

Know how to label this

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39

Can you label the inner and external ear structures of the dog?

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You better!

40

What nerve innervates the rostroauricular and caudoauricular muscles of the pinna?

Motor branches of the facial nerve

41

What does the external ear consist of?

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The auricle (pinna) and external acoustic meatus

42

What does the middle ear consist of?

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The ossicles, tympanic cavity, and bulla

43

What does the inner ear consist of?

Cochlea and semicircular canals

44

In horses, how is the junction between the cartilaginous and osseous portions of the external acoustic meatus grossly identified?

An abrupt change from pigmented to nonpigmented epithelium.

45

Match the Tympanic membranes: Pig, Goat, Horse, Dog (ignore the bottom 2 images)

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A, Horse. In the horse, the tympanic membrane (tympanum) is more round than other species. The manubrium of the malleus forms a very shallow arc and is centrally located in the tympanum.

B, Dog. The tympanum is oval to comma-shaped, and the manubrium of the malleus is C-shaped. 

C, Pig. Similar to the dog, but the manubrium of the malleus is shorter and straighter. 

D, Goat. Ruminants tend to have a more triangular-shaped tympanic membrane. In both pigs and ruminants, the manubrium of the malleus is more rostral and medial than in other species. 

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