Ear

Question 1

which bone houses the cavities of the ear?

name its 4 components

Answer 1

The Temporal Bone

Question 2

what is the petrous bone?

Answer 2

Question 3

in relation to temporal bone parts, the external acoustic meatus consists mostly of the___________

Answer 3

tympanic plate

Question 4

parts of ear

Answer 4

Question 5

what goes through the internal acoustic meatus? which cranial fossa does it lie in?

Answer 5

facial and vestibulocochlear cranial nerves.

7 & 8

Question 6

Answer 6

Right ear

Process of the mallelous is pointing to the left

Question 7

what do u find inside a cutt section of the mastoid process?

Answer 7

it has several air filled spaces within it called the mastoid air cells

ALAA “cells” in this context = small spaces

Question 8

what muscles attatch to the mastoid process?

Answer 8

sternocleidomastoid and digastric muscles

Question 9

how does the mastoid air cells communicate with the middle ear cavity? clinical relevance

Answer 9

Question 10

Label ear

Answer 10

Question 11

label the External Ear

Answer 11

Question 12

anatomy of external acoustic meatus

How long is it?

Answer 12

• cartilaginous tube laterally ( (outer 1/3) )
• bony canal medially lying in the temporal bone. ((inner 2/3) )

2.5 cm

Question 13

how can we view the ear?

Answer 13

bc the ear canal is Sigmoid shape>> need to pull ear up and back to

straighten when examining

Question 14

what forms the WAX of the ear?

Answer 14

The meatus is lined by skin secreting cerumen (which is modified sebum) that gives protection for the delicate meatal skin.

The discarded cells of the skin together with cerumen form the>>> WAX

Question 15

Despite similarities in their names, the internal and external acoustic meatus are not one continuous bony channel! !!!

Answer 15

chill ok

Question 16

describe the fibrous tympanic membrane

Answer 16

“ear drum” shallow cone with its apex pointing medially.

It is translucent allowing visualisation of some structures within the middle ear, most notably, the malleus to which the apex of the eardrum is attached.

Question 17

Middle ear anatomy And function

Answer 17

Ossicles and an Air Filled Cavity

The middle ear, or the tympanic cavity, contains the ossicles that transmit vibrations from the tympanic membrane to components of the inner ear.

The middle ear cavity is air-filled and enclosed from the external environment.

Question 18

Bones of middle ear? Function and how r they connected?

Answer 18

The handle of the malleus is attached to the tympanic membrane while its body articulates with that of the incus. The incus then articulates with the stapes then opens at oval window

Connected via synovial joints and relay vibrations from the tympanic
membrane to the oval window of the cochlea (inner ear)

• Transmitting vibration from an air medium to a fluid-medium
• The ossicles amplify and concentrate sound energy from the eardrum to the oval window.

Question 19

look how tiny they r

Question 20

How does middle ear communicate w/ the external environment ?

Answer 20

via the pharyngotympanic (Eustachian) tube when this opens

Question 21

pharyngotympanic (Eustachian) tube anatomy & functions

Answer 21

Question 22

How do u open the pharyngotympanic (Eustachian) tube?

Answer 22

The pharyngotympanic (Eustachian) tube is usually closed, it opens by the pull of attached palate muscles when swallowing or yawning.

You might have noticed this as your ears ‘popping’.

Question 23

how does the Pharyngotympanic tube differ in children?

Answer 23

Question 24

Important Anatomical Relations of the Ear

Answer 24

Question 25

which nerve has an important relationship w/ the middle ear?

Answer 25

Question 26

anatomy of the Inner Ear and function

Answer 26

The inner ear, also called the *labyrinth "maze"* *consists of a series of channels or canals hollowed out of the petrous temporal bone **(the bony labyrinth)** which surround a series of tubes or ducts, known as the **membranous labyrinth.*** The **_cochlea_** converts vibration into an electrical signal (action potential) which is perceived as sound The **_vestibular apparatus_** is involved in maintaining our sense of position and balance

Question 27

Label vestibular apparatus

Answer 27

Question 28

The ***ducts*** (“tubes”) forming the _membranous labyrinth_ are shaped to form 4 structures: what r these ducts filled with?

Answer 28

All of these ducts are filled with ***endolymph.***

Question 29

what about the bony labyrinth ?

Answer 29

surrounds and mirrors the shape of these membranous ducts (tubes). These bony shapes are called ‘***canals***’ * the bony labyrinth surrounding the semicircular duct is called the **semicircular canal** * the bony labyrinth surrounding the utricle and saccule is the **vestibule.** * Between the membranous and bony labyrinth is a fluid called **perilymph.**

Question 30

*anatomy of cochlea* what sets up movements of the fluid in the cochlea?

Answer 30

The cochlea is our organ of hearing. It is fluid filled tube. Movements at the ***oval window*** set up movements of the fluid in the cochlea .

Question 31

what r the special sensory cells in the cochlea? where r they located? what r their function?

Answer 31

in the organ of Corti! Waves of fluid cause ***movement*** of special sensory cells (stereocilia) within the cochlear duct which generate AP in CN VIII

Question 32

How do we hear?

Answer 32

Question 33

what forms the components of the balance system? how do they coordinate balance?

Answer 33

The *_stereocilia_* in the **utricle and saccule** respond to _rotational acceleration_ and the _static pull of gravity_, while receptors in the **semicircular ducts** respond to rotational acceleration in three different planes (mirroring their arrangement).

Question 34

what causes the stercocilia to bend?

Answer 34

Movement of the head and body leads to movement of fluid within these inner ear structures, causing the stereocilia to bend. This “bending” generates an AP that is relayed via the vestibular part of the vestibulocochlear nerve, and is perceived as our sense of position and balance.

Question 35

function of Stapes? innervation

Answer 35

tendon of stapes protrudes from the stapedius muscle and holds onto the stapes and pulls it backwards, restricting its movement, this is an advantage for us limiting loud sounds. if stapes muscle cotnracts it will reduce the ossicular chan movements and prevent inner ear from excessive stimulation & prevent damge to the hair cells! facial nerve!

Question 36

facial nerve relation with middle ear?

Answer 36

Question 37

label ear

Answer 37

Question 38

label temoral bone parts

Answer 38

Question 39

label the tympanic membrane how do u know which is left or right?

Answer 39

this is the Normal Right Tympanic Membrane

Question 40

function of round window?

Answer 40

This is the round window, an opening in the inner ear which is covered by a membrane. The round window, and its flexible membrane, is vital to **allow movement of fluid within the cochlea**. Without the round window, the stapes footplate would be pushing against a fluid-filled cochlea (via its action at the oval window) that would be uncompressable. As a result no movement of fluid would occur. The movement of fluid needs to occur to stimulate movement of the hair cells within the cochlea , so that electrical impulses can be generated down the cochlear nerve (allowing perception of sound i.e. hearing)