Special Senses Part 3 - The ear Flashcards

1
Q

What is the general function of the external, middle and internal ear?

A

External ear:
Collects sounds waves and channels them inward.

Middle ear:
Conveys sound vibrations to the oval window.

Internal ear:
Houses the receptors for hearing and equilibrium.

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2
Q

Where do the waves collected by the external ear travel through?

A

These waves travel from the auricle –> external acoustic meatus (or external auditory canal) –> towards the tympanic membrane.

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3
Q

Label the bone features of the ear?

A
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4
Q

What is the middle ear called and where is it located?

A

–> It is also called the tympanic cavity.
–> It is a small, air-filled cavity within the petrous part of the temporal bone.

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5
Q

Name the 3 auditory ossicles?

A

Malleus
Incus
Stapes

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6
Q

Fill in the blank of the 3 auditory ossicles:

The malleus is attached to the _______________ membrane.
The incus articulates with the __________ & __________ bones.
The stapes covers the ______________ window.

A
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7
Q

What are the 2 muscles of the middle ear?

A

Stapedius
Tensor tympani

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8
Q

Fill in the blank of the 2 muscles of the middle ear which prevent damage from excessively loud noises:

Stapedius restricts movement of the _________________.
Tensor tympani restricts movement of the ______________.

A
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9
Q

What does the auditory tube connect?

A

It connects tympanic cavity
with nasopharynx.

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10
Q

What is the function of the auditory tube (or pharyngotympanic
tube)?

A
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11
Q

What are the 2 openings into the osseous labyrinth?

A

Oval window
Round window

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12
Q

Fill in the blank of the 2 windows of the middle ear:

The oval window opens into the upper part of the osseous (bony)
cochlea called the scala _____________.
It is covered by the ___________ (bone).
The round window opens into the lower part of the osseous
cochlea called the scala _____________.
It is covered by the ________________ (membrane)

A
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13
Q

Label the parts of the middle ear?

A
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14
Q

What does the inner ear contain and what is its function?

A

The vestibulocochlear organ, concerned with the reception of sound and the maintenance of balance.

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15
Q

What are the 2 main divisions of the inner ear?

A

The outer bony labyrinth
The inner membranous labyrinth

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16
Q

Name the 3 parts of the bony labyrinth?

Identify where the bony labyrinth is located and what fluid it is filled with?

A

Vestibule
Cochlea
Semicircular canals

Location:
A space within the petrous part of the temporal bone and is filled with perilymph.

17
Q

What do each part of the bony labyrinth contain?

A

Cochlea:
Contains the cochlear duct of the membranous labyrinth.

Vestibule:
Contains the utricle and saccule of the membranous labyrinth.

Semicircular canals:
Contain the semicircular ducts of the membranous labyrinth.

18
Q

What does the vestibule of the bony labyrinth open into?

A

Opens into the tympanic cavity via the _____________ window.

19
Q

What does the membranous labyrinth consist of?

Where is the membranous labyrinth suspended and what is it filled with?

A
  1. Consists of a series of membranous sacs and ducts.
  2. Suspended within the
    bony (osseous) labyrinth and is filled with endolymph.
20
Q

Name the 4 parts of the membranous labyrinth?

A

Cochlear duct
Utricle
Saccule
Semicircular ducts

21
Q

Where does the cochlear duct of the membranous labyrinth open into?

A

Opens directly into the saccule.

22
Q

What is the ‘spiral organ’ or ‘Organ of Corti’?

What is its function?

A

The receptor organ for hearing, which is located within the membranous cochlear duct.

Function:
Plays the primary role in the transduction of sound.

23
Q

What is the name of the specialised sensory epithelium located in the utricle?

What is its function?

A
24
Q

Where does the semicircular ducts of the membranous labyrinth open into?

A

Open into the utricle and contain the ampullary crests.

25
Q

What is the function of the semicircular ducts of the membranous labyrinth?

A
26
Q

What is the function of the external and middle ear?

A

They are both involved in hearing only.

27
Q

What is the function of the inner ear?

A

Functions in both hearing and equilibrium.

28
Q

Name the receptors for equilibrium and specify their location?

A

Vestibular receptors.

Location:
They are found within the vestibular apparatus of the membranous labyrinth, which includes the semicircular canals and the utricle & saccule in the inner ear.

29
Q

Name the receptors for hearing and specify their location?

A

Organ of corti (spiral organ)

Location:
Located within the membranous cochlear duct of the membranous labyrinth.

30
Q

Briefly outline the auditory pathway to the brain?
(Steps 1-3)

A
  1. Sound waves enter the ear and cause the tympanic membrane to vibrate.
  2. Tympanic membrane vibration moves auditory ossicles; sound waves are amplified.
  3. The stapes at the oval window generates pressure waves in the perilymph within the scala vestibuli.
31
Q

Briefly outline the auditory pathway to the brain?
(Steps 4-5)

A
  1. Pressure waves cause the vestibular membrane to move. Hair cells in the spiral organ are distorted, causing a nerve impulse in the cochlear branch of the vestibulocochlear nerve (CN VIII).
  2. Remaining pressure waves are transferred to the scala tympani and exit the inner ear via the round window.
32
Q

Briefly outline the auditory pathway to the brain?
(Steps 6)

A

Sensory neurons in the cochlear branch of each vestibulocochlear nerve terminate in the medulla oblongata on the same side of the brain.
6. Medulla oblongata –> axons ascend to the midbrain –> then to the thalamus –> then to the primary auditory cortex of the temporal lobe.

33
Q

Label all the parts of the external, middle and internal ear?

A
34
Q

What part of the ear contains the ossicles?

A

Tympanic cavity

35
Q

What opens in the middle ear?

A

The oval window opens into the scala vestibuli.

36
Q

The vestibule…

A

Is part of the osseous labyrinth.

37
Q

The cochlear duct…

A

–> Includes the Organ of Corti.
–> Divides the cochlear canal into scala vestibuli and scala tympani.

38
Q

Semicircular ducts…

A

Houses the macula for equilibrium.