Anatomy - Ear Flashcards Preview

Block 3 - Resp > Anatomy - Ear > Flashcards

Flashcards in Anatomy - Ear Deck (16):
1

Different parts of the ear

- external: cartilage, tube
- middle: cavity, bone, muscles
- internal: canal, sacs

- external and middle ears are mechanical - pass on the sounds
- internal ear is electrical - processes the sound

2

External ear 2 parts

- auricle
- external acoustic meatus

3

External ear

1) Auricle

- parts: skin, cartilage, ligaments, mucles
- nerves: V3, C2-3
- Function: protection, localise sound

4

External ear:

2) external acoustic meatus

- 1 inch long, not straight, concave anteriorly
- parts: lateral 2/3 are cartilaginois made of hairs and glands, medial third is made up of bone
- relations: parotid anteriorally, mastoid air cells posteriorally
- nerves: V3, C2-3
- function: conduct and amplify sound towards tympanic membrane, protects and humidy the air

5

Clinical issues of external ear

- ear viewing
- self-cleaning system

6

Middle ear contents

- tympanic membrane
- ossicles
- muscles
- cavity

7

Middle ear: tympanic membrane

- partitions external and middle ears
- concave laterally
- Surface: distinct covers
- parts: pars tensa attaches to malleus, pars flaccida
- nerves: V3/ X innervate the lateral part of tympanic membrane, IX is very sensitive and innervates the medial part of tympanic membrane

- Functions: receive sounds, first vibrator

8

- clinical issues of tympanic membrane

- color: becomes red when inflammed
- cone of light
- perforations: small ones self correct but larger ones may require surgery

9

Middle ear: ossicles

- types: malleus, incus, stapes (from tympanic membrane to inner ear). Connected by synovial joints
- workings: system of levelrs, some move, others are fixes
- function: transfer vibrations towards inner ear

- CLINICAL ISSUE: commonly infected

10

Muscles of middle ear

- tensor tympani: from auditory tube to handle of malleus
- Stapedius: from posterior cavity to stapes

- Nerves: V3 for tensor, VII for stapedius

- Functions: dampen vibrations of tympanic membrane

- clinical issues: hyperacusis if vibrations are not dampened

11

Internal ear two parts

- osseous labyrinth
- membranous labyrinth

12

Osseous labyrinth

- structure: cavity in temporal bone, contains perilymph

- parts: semicircular canals, vestibule, cochlea

13

Membranous labyrinth structure

- sacs continuous with osseus labyrinth
- closed system
- contains endolymph - important that it doesnt mix with perilymph

- endolymph production requires melanocyte - thats why albino may have trouble hearing

14

Membranous labyrinth: parts

- semicircular ducts (in canals): cupula (kinetic labyrinth - movement)
- utricle and saccule (in vestibule): macula (static labyrinth - position)
- cochlea duct (in cochlea): organ of corti (hear)

15

Membranous labyrinth nerves and function

- nerve: vestibulocochlear. Vestibular to cupula and macula, cochlear to organ of corti

- function: fluid shifts, position, movement, hearing

16

Clinical issues of internal ear

- conductive deafness: external or middle ear
- Sensorineurol deafness: inner ear

- Meniere disease: vestibular and auditory disturbance, mixing of endolymph and perilymph. Occurs because of excessive nause, trauma or virus

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