Ear

Front 1

List the three devisions of the ear

Back 1

• external ear

• middle ear (tympanic cavity)

• internal ear (labyrinth)

Front 2

List the 2 units of the external ear

Back 2

• auricle (pinna)

• external accoustic meatus (ends at the tympanic membrane)

Front 3

Describe the features of the auricle

Back 3

• most of the ear consist of elastic cartilage except the lobe/lobule

• the cartilaginous structure an outer an inner curvature

- helix (outer curvature)

- antihelix (inner curvature) runs parallel with the helix

• the antihelix branches into to cura: superior and inferior crus

• hollow depression in the auricle (concha) directs sound into the external meatus

• anterior to the external meatus is the tragus. Opposite the tragus is the antitragus

Front 4

Describe the function of the auricle

Back 4

Capture and directs sound waves towards the external acoustic meatus

Front 5

Describe the feature of the external accoustic meatus

Back 5

•Sigmoid-shaped (S-shaped) tube that extends from the concha of the auricle to the tympanic membrane

• the external 3rd of the meatus is formed by cartilage.

• the last 2 3rds of the meatus is formed by temporal bone

Front 6

Describe the function of the external accoustic meatus

Back 6

Pathway for sound waves to hit the tympanic membrane (transmit sound to the middle ear)

Front 7

Describe the feature of the tympanic membrane

Back 7

• lies at the distal end of the acoustic meatus

• connective tissue structure

• external membrane covered with skin, internal membrane covered with mucous

• attaches to the tympanic bone by a fibrocartilagenous ring

Front 8

List the cavities of the middle

Back 8

• tympanic cavity - (contain the auditary bone) lies medially to the tympanic membrane

• epitympanic recess - lies superior to the tympanic cavity

Front 9

Which structure marks the end of the external auditory meatus

Back 9

Tympanic membrane

Front 10

The tympanic membrane is connected to the surrounding bone by a fibrocartilaginous ring. Which bone is the ring connected to?

Back 10

Temporal bone

Front 11

List the auditory bones/ossicles in the tympanic cavity of the middle ear

Back 11

• malleus

• incus

• stapes

Mneumonic MIS

Front 12

What is the overall function of the auditar ossicles in the inner ear

Back 12

Sound vibrations cause the tympanic membrane to vibrate which cause oscillation of the ossicle that transmit the sound waves from the tympanic membrane to the oval window of the inner ear

Front 13

Which structure forms the roof of the middle ear

Back 13

Petrous part of the temporal bone

Front 14

Where are the mastoid air cells in relation to the epitympanic recess?

Back 14

Posterior

Front 15

What are the 2 main functions of the vestibulocochlear organs in the inner ear?

Back 15

• convert mechanical signals from the middle ear to electrical signals (to the brain)

• maintain balance by detecting position and motion

Front 16

Where in the temporal bone is the inner ear located?

Back 16

Petrous part of the temporal bone

Front 17

List the two main components of the inner ear

Back 17

Bony labyrinth

Membranous labyrinth

Front 18

List the three parts of the bony labyrinth in the inner ear

Back 18

• cochlea

• vestibule

• 3 semi-circular canals

Front 19

Describe the vestibule of the bony labyrinth in the inner ear and name the parts of the membranous labyrinth that it houses

Back 19

• central part of the bony labyrinth

• separated from the middle ear by the oval window

• communicates anteriorly to the cochlea and posteriorly to the semi-circular canals

• houses the saccule and utricle of the membranous labyrinth

Front 20

Describe the cochlea of the bony labyrinth in the inner ear and which part of the membranous labyrinth does it house?

Back 20

• houses the cochlea duct of the membranous labyrinth

• twists itself around the modiolus bone which produces a cone that point anterolaterally

• contains two perilymph-filled chambers:

- scala vestibuli

- scala tympani (terminates at the round window)

Front 21

Describe the semi-circular canals of the bony labyrinth in the inner ear

Back 21

• three canals at right angles from each other:

- anterior

- lateral

- posterior

• contain semi-circular ducts which are responsible for balanca

• situation superoposterior to the vestibule

• swelling at their bases - ampullae

Front 22

List the 4 membranous labyrinths in the inner ear

Back 22

• cochlear duct

• saccule and utricle

• semi-circular duct

Front 23

Describe the cochlear duct of the membranous labyrinth in the inner ear

Back 23

• located within the bony scaffold of the cochlea

• the presence of the duct creates two canals: one above (scala vestibuli) and one below (scala tympani)

Front 24

Describe the saccule and utricle of the membranous labyrinth in the inner ear

Back 24

• membranous sac in the vestibule

• detect movement in the verticle plane and acceleration in the horizontal planes

• the utricle receives three semi-circular ducts

• the saccule receives the cochlear duct

Front 25

Describe the semi-circular ducts of the membranous labyrinth in the inner ear

Back 25

• located within the semi-circular canals

• upon movement, the endolymph in the ducts change speed and/or direction

• sensory receptors in the ampulla (base of the semi-circular canals) detect the change in endolymph and transmit this info to thr brain for processing balance