What are the 3 regions of the ear?

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1) External ear

2) Middle ear

3) Inner ear

1) Hearing: frequency, loudness & direction of sound waves (all 3 regions)

2) Equilibrium: detect gravity & movements of head (inner ear) 

Name the strutures of the external ear:

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1) Auricle/pinna

2) Concha

3) External auditory meatus

Name the structures of the outer ear:

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1) Helix

2) Antihelix

3) Antitragus

4) Lobe

5) Tragus

6) Concha

What is the skeleton of the outer ear made up of?

What part of the outer ear has no cartilage?

Name the structures of the cartilage of the outer ear:

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Elastic cartilage

Lobe

1) Spine of the helix

2) Crus of helix

3) Lamina of tragus

4) Fissure of tragus

5) Tail of helix

6) Helix

What is the EAM composed of?

What is it lined w & why?

Cartilage & bone

Glands that produce serumen(ear wax) to trap particles preventing it from entering near ear drum

Name the structures in the middle ear:

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1) Petrous portion of the temporal bone

2) Malleus

3) Incus

4) Stapes

5) Stapedius

6) Round window

7) Auditory tube

8) Tympanic cavity

9) External auditory canal

10) Tympanic membrane

What are the 2 membranes in the middle ear?

What shape is the ear drum?

What seals the oval window?

What is the round window continuous with?

What is concidered the opening of the inner ear?

- Tympanic membrane (ear drum)

- Membrane of round window (2nd tympanic membrane)

Conical

Stapes

Cochlea

Oval window

Name the parts of the tympanic membrane:

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1) Flaccid part

2) Cone of light

3) Umbo

4) Tense part

- Auditory tube -> pharynx

- Mastoid air cells

What middle ear bone is this?

What structure is it directly connected to?

Name the parts:

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Malleus

Ear drum

1) Head

2) Neck

3) Lateral process

4) Anterior process

5) Manubrium

What middle ear bone is this?

Name the parts:

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Incus

1) Body

2) Short process

3) Long process

4) Lenticular process

What middle ear bone is this?

Name the parts:

What part inserts into the oval window?

What is the smallest bone in the body?

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Stapes

1) Neck

2) Head

3) Posterior crus

4) Anterior crus

5) Footplate

Footplate

Stapes

How does the middle ear function?

What are the 2 mechanism that help the middle ear transmit sound into the inner ear?

1) Vibration -> Malleus -> incus ->stapes vibrates mecanically (pushes in & out on the oval window)

- Lever arm mechanism

- Hydrolic mechanism

What middle ear muscle is this?

What nerve is it innervated by? 

What bone does it attach to?

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Tensor tympani

V3 (mandibular division of trigeminal nerve 5)

Malleus

What nerve is found in the middle ear?

What does 1 nerve give rise to?

What type of innervation does it provide & where?

Name the nerves:

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Chorda tympani

Chorda tympani

- PS to bottom of mouth

- Sensory (taste) back from anterior of tongue

1) Facial n

2) Chorda tympani

What nerve is the stapedius tendon innervated by?

What 2 muscles are found in the middle ear?

What are their functions?

Facial nerve (7)

- Stapedius

- Tensor tympani

Pull on ossicles to prevent overstimulation of inner ear

Name the structures:

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2) Facial n (7)

3) stapedius tendon

What nerve innervates the ear drum?

What nerves innervate the round window?

Chorda tympani n

- CN 9 glossopharyngeal -> tympanic n -> tympanic plexus -> lesser petrosal n

What are the 3 major portions that make up the body labyrinth?

What is the superior hole?

What is the inferior hole?

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1) Semicircular canals

2) Vestibule

3) Cochlea

Oval window

Round window

Name the structures in the membranous labyrinth:

Where are these found?

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1) Utricle

2) Semicircular ducts

3) Saccule

4) Cochlear duct

Inside the boney labyrinth

Where are the sensory cells found?

What do they help detect? 2

Inside the saccule

- Balance (semicircular canals)

- Hearing (cochlea)

What fluid is found in membranous tubes?

What fluid is found in the boney tubes?

Endolymph

Perilymph

What does the brain use to figure out the direction of gravity & sound?

Name the structures:

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Hair cells

Stereocillia

What is the connection of the boney labyrinth at the tip of the cochlea called?

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What is the path of sound thru the cochlea?

What is found in the middle? 

How does sound stimulate hair cells?

What is the name of where the hair cells are found?

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Thru:

1) Scala vestibuli

2) Helicotrema

3) Scala tympani

Cochlear duct/scala media?

Sound waves crest in 1 -> Press down on scala media -> stimulate hair cells

Organ of corti

1) Scala vestibuli

2) Vestibular membrane

3) Osseus spiral lamina

4) Scala tympani

5) Organ of corti

6) Basilar membrane

7) Spiral ligament

8) Hair cells

9) Cochlea

Where do high frequency/pitch sound crest?

Where do low frequency/pitch sound crest?

Name the ends of the cochlear duct:

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Early/base end (SV)

Late apex end (SV)

1) Apex

2) Base

What are the 2 different types of hair cells?

What are their functions?

What membrane moves to detect sound?

- Inner hair cells

- Outer hair cells

- Inner: detect sound

- Outer: control vibrations of basilar membrane (filters out unnecessary sound)

Basilar membrane

What is found in the vestibule?

Where are the hair cells found?

Name the structures of the vestibule:

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Hair cells

- Saccule

- Utricule

1) Vestibule

2) Utricule

3) Saccule

What the function of odoliths?

How are we able to detect gravity?

Add mass

Position of head pulls on genatinous layer -> moves hair cells -> signals brain

Name the sturctures of the hair cells found in the semicircular duct:

Where are these hair cells found?

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Cupula

On the base of the semicircular canal

- Movement back & forth

- Dynamic equilibrium

Movement dectected by:

1) Semicircular canal

2) Vestibule

3) Cochlea

1) Circular movement

2) Gravity/momentum of body

3) Sound