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RUSVM Anatomy 2 > Ear > Flashcards

Flashcards in Ear Deck (21)
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1

Three main divisions of the terrestrial mammalian ear:

External (outer) ear, Middle ear, Inner ear

2

External ear

-auricle (pinna): collects sound waves from environment
-ear canal: vertical and horizontal parts

3

Middle ear

-housed in tympanic part of temporal bone
-tympanic membrane (ear drum)
-tympanic bulla (tympanic cavity)
-auditory ossicles e/ associated muscles and ligaments
-communicates w/ nasopharynx via the auditory tube

4

Inner ear

-responsible for balance(semicircular canal)
-Housed in petrous part of temporal bone
-osseous labyrinth
-membranous labyrinth (organs of inner ear)

5

Three divisions of ear allow for transformation of sound pressure waves into electrical energy

-external ear captures sound waves & transmits energy to the middle ear via tympanic membrane
-ossicles of middle ear convert these pressure waves into mechanical energy
-vibrations at oval window by the stapes produces pressure waves e/in perilymph of inner ear
-movement of perilymph displaces the tectorial and basement membranes, stimulating firing of electrical impulses by cochlear neurons

6

The external ear is necessary for sound collection and sound localization

-visible portion of external ear is supported by irregularly shaped auricular cartilage
-proximal end of this cartilage forms a canal (vertical and horizontal ear canals)
-distal end of this cartilage forms pinna, funnel to concentrate waves

7

Shape of pinna is dependent upon

-the composition of the fibroelastic auricular cartilage
-the collagen/elastin composition varies among species and breeds
-non-erect, erect, semi-erect
-size & shape determines which sound frequencies are collected optimally and also many reduce noise
-vasculature helps cool body

8

What gland produces ear wax?

ceruminous gland
(adenomoas in cats)

9

Where do ticks like to collect?

cutaneous marginal pouch

10

Annular cartilage

holds ear to skull
-connects cartilagenous meatus of horizontal canal w/ bony external acoustic meatus

11

Scutiform cartilage

"sesmoid bone" attachment for auricular muscles and tendons
-flat, boot-shaped cartilage
-located medial & rostral to base of auricle
-aids in redirection

12

Auricular muscle groups that allow auricle of each ear to move towards a sound source

-rostral auricular group
-caudal auricular group

13

The middle ear is located in the air-filled tympanic cavity of the

temporal bone

14

Only connection to external environment occurs through the

auditory tube

15

What is the expanded ventral portion of the tympanic cavity?

tympanic bulla

16

What is the bony promontory?

expansion of the petrous temporal bone
-protrudes into dorsal region of tympanic cavity

17

Manubrium of the malleus is embedded in the

tympanic membrane

18

Vibrations of the tympanic membrane move to the

malleus

19

Contraction of ______ dampens the movement of the malleus

tensor tympani muscle

20

Diarthrotic (synovial) joints connect the middle ear ossicles. Movement of the malleus will result in the movement of

the incus and stapes

21

Contraction of the ________ dampens the movement of the stapes at the oval window

stapedial muscle