Ear Final Exam

Peripheral Auditory System

Function: Collect the sound waves and transform them from mechanical to electrochemical energy into the brain

Central Auditory system

interpret the electrochemical signals and differenciate the sounds

microtia

being born with a small pinna

anotia

complete absence of the pinna (fails to develop)

What is unique about the external auditory meatus in children

Their EAM is more horizontal- makes it easier to get things stuck

In adults, what is helpful about the structure and celia of the EAM?

It slopes downward to help drain fluid and keep dust, insects, and moisture out of the middle ear.

What is one reason why ear infections so painful?

Epithelial and connective tissue is tightly bound to the cartilage and bone of the ear

What 5 components make up the Middle Ear?

1. Tympanic membrane

2. Middle ear cavity

3. Auditory Ossicles (Ear bones)

4. Middle ear muscles

5. Eustachian tube

How many layers of tissue are in the tympanic membrane?

3 layers (two in the middle makes 4)

What are the different layers of tissue in the tympanic membrane

1. Outer Cuticular Layer (continuous with the outside tissue)

2. Intermediate Fibrous Layer (Made up fo 2 layers)

a. Superficial layer = center-outward fibers

b. deeper layer = circular

3. Inner mucous layer continuous with inside

Pars flaccida

anterior malleolar fold

pars tensa

malleolar stria

cone of light

temporal bone

umbo

posterior malleolar fold

What is the point of the cone of light?

The reflection of the light of the otoscope off of the tympanic membrane signals a healthy ear drum

Tensor tympani muscle

Stapedius muscle

The middle ear cavity is filled with

air

The medial wall of the middle ear cavity contains the

oval window, round window and promontory

The posterior wall of the middle ear cavity contains the

pyramidal eminence containing the stapedius muscle

What fits into the oval window?

the footplate of the stapes

What is the purpose of the round window?

To displace fluid pushed inward by the stapes, and separate the air and fluid

This whole bone

malleus

facet for incus

head of malleus

neck of malleus

lateral process

facet for incus

whole bone

incus

corpus (body)

short process

long process

articular facet

lenticular process

this whole bone

stapes

posterior crus

head of stapes

anterior crus

Give the insertion, function, and innervation of the stapedius muscle

Insertion: neck/ head of stapes
Function: primary muscle involved with the acoustic reflex

Innervantion: Facial nerve VII

Give the insertion, function, and innervation of the Tensor tympani muscle

Insertion: Upper manubrium/ anterior process of malleus
Function: involved in triggering the acoustic reflex

Innervation: trigeminal nerve CN V

What is the acoustic reflex

the reflex triggered by loud sounds to dampen transmission to avoid damages

where is the eustachian tube

establish connection between the middle ear and the nasopharynx

What is the function of the eustachian tube?

opens to match the pressure outside with the pressure in the middle ear and remove harmful fluid

What muscles open the eustachian tube

levator veli palatini and the tensor veli palatini

Why are ear infections easier for kids

Children’s eustachian tube are more horizontal and can get infections from fluid in the middle ear easier

utricle

saccule

Vestibule

What two main parts make up the Inner ear

1. The bony labyrinth

2. The membranous labyrinth

What 3 parts make up the bony labyrinth

1. Semicircular canals

2. Vestibule

3. Cochlea

What 3 parts make up the membranous labyrinth

1. the membranous semicircular canals

2. utricle and saccule

3. cochlear duct

Chrisae within ampillae

vestibular duct

cochlear duct

tympanic duct

saccule

utricle

what do the ampulla contain

sensory cells of the semicircular canal that tell movement

perilymph

bony labyrinth (makes up most of the cochlea)

endolymph

membranous labyrinth

the cochlea is ________?

tonotopic

the cochlea’s tonotopic nature means that

sounds (tones) are mapped on the cochlea by a frequency on each part

top cinnamon roll portion of the cochlea

helicotrema

center pillar in cochlea

modiolus

each layer of tube of cinnamon roll

spiral lamina

internal auditory meatus

endolymphatic duct

The function of the endolymphatic duct is to

connect the saccule and utricle

Everything in diagram except for the cochlea is part of the ________

vestibular system (equilibrium)

What two parts make up the vestibular system? (and their functions)

1. Kinetic part

• the perception of the rotation and acceleration of the head

2. Static part

• the perception of the position in the vertical plane (sense of gravity and where you are in space)

What are the crista ampillaris

sensory cells of the semicircular canal

Where does the perception of sound in the body transfer from mechanical into electrochemical energy?

hair cells in cochlea

The top, gelatinous portion inside the crista ampullaris where bundles of hairs are

cupola

The jumping of the eyes from side to side is called____ and is characteristic of…

a nystagmus ; vertigo

The damage of vestibular system is manageable with

sight information from eyes

List the membrane, sensory cells, and membrane cover of the following bone:
Cochlea

1. Cochlear duct

2. Spiral organ of Corti

3. tectorial membrane

List the membrane, sensory cells, and membrane cover of the following bone: Semicircular Canals

1. Membranous semicircular canals

2. crista ampullaris

3. cupola

List the membrane, sensory cells, and membrane cover of the following bone:

1. utricle saccule

2. macula

3. otolithic membrane

upper triangle of perilymph

scala vestibuli

bottom triangular space under the basilar membrane

scala tympani

middle space made of endolymph

cochlear duct

top membrane separating membrane and bone

Reissner’s membrane

bottom membrane holding organ of corti

Basilar membrane

Cells of Claudius

Cells of Hansen

Outer tunnel

outer hair cells

tectorial membrane

inner hair cell

inner tunnel (tunnel of Corti)

basilar cells

inner phalangeal cells

outer phalangeal cells

basilar membrane

What are the two main cell divisions of the Spiral organ of Corti?

1. The supporting cells

2. The receptor cells

What makes up the supporting cells of the Spiral organ of Corti?

a. inner phalangeal cells

b. rods of corti

c. outer phalangeal cells (cells of Deiters)