Lecture 16: Anatomy and Histology of the Ear Flashcards

1
Q

What composes the external ear?

A

Auricle to Tympanic Membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What composes the middle ear?

A

Tympanic Membrane to Oval Window

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What composes the inner ear?

A

Oval Window to Internal Acoustic Meatus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What type of cartilage is the external ear mostly made up of?

A

Elastic Cartilage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What supplies the external ear?

A

Posterior Auricular Artery (from ECA)

Superficial Temporal Artery (from ECA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What provides sensory innervation to the external ear?

A
  1. Facial Nerve
  2. Cervical Plexus: Lesser Occipital and Greater Auricular Nerves
  3. Auriculotemporal Nerve (V3)
  4. Vagus/Glossopharyngeal Nerve
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What innervates the superior part/roof of the external acoustic meatus?

A

Facial Nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What innervates the posterior part of the external acoustic meatus?

A

Greater Auricular Nerve (Cervical Plexus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What innervates the anterior part of the external acoustic meatus?

A

Auriculotemporal Nerve (V3)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What innervates the inferior part/floor of the external acoustic meatus?

A

Vagus: Arnold Nerve

-plays a role in the cough reflex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What glands make ear wax?

A

Ceruminous Glands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the composition of the external acoustic meatus?

A

Outer ⅔: Soft CT and Cartilage (similar to external ear)
-where you can see ceruminous and sebaceous glands + hair follicles
Inner ⅓: Just skin and bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where is the cone of light?

A

Anterior, inferior quadrant of Tympanic Membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What makes up the roof of the middle ear?

A
Tegmental Wall (from Temporal Bone)
-Separates ear from brain/middle cranial fossa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What makes up the floor of the middle ear?

A

Jugular Wall

-Separates ear from bulb of Internal Jugular Vein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What makes up the lateral wall of the middle ear?

A

Membranous Wall (going to external ear)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What makes up the medial wall of the middle ear?

What is found at this wall?

A

Labyrinthine Wall (Oval and Round Windows)

  • Lateral Semicircular Canal
  • Facial Canal and Nerve
  • Promontory of Labyrinthine Wall
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What makes up the posterior wall of the middle ear?

A

Mastoid Wall

-Separates tympanic cavity from mastoid air cells and facial canal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What can be found at the anterior wall of the middle ear?

A

Pharyngotympanic Tube
Tensor Tympanic Muscle
-Separates Tympanic Cavity from Internal Carotid Artery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What does the pharyngotympanic tube connect?

A

Middle ear to nasopharynx

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does the pharyngotympanic tube do?

A

Equalize pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What two muscles expand the pharyngotympanic tube?

A

Levator Veli Palatini Muscle

Tensor Veli Palatini Muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What type of epithelium is found on the pharyngotympanic tube?

A

Pseudo-stratified Epithelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What three bones make up the auditory ossicles in the middle ear?
What pharyngeal arches are they from?

A

Malleus (PA 1)
Incus (PA 1)
Stapes (PA 2)

25
Q

What does the auditory ossicles do?

A

Transmit sound from the air to the fluid filled concha

26
Q

What does the Tensor Tympani Muscle do?

What nerve innervates it?

A

Dampens loud sounds by pulling on handle of malleus

Innervated by CN V3

27
Q

What does the Stapedius Muscle do?

What nerve innervates it?

A

Dampens vibrations and limits excess movement of stapes bone (at the neck)
Innervated by CN VII

28
Q

Where is the bony labyrinth located?

A

Petrous Region of Temporal Bone

29
Q

What separates bony labyrinth with membranous labyrinth?

A

Perilymph

30
Q

What lymph is found in membranous labyrinth?

A

Endolymph

31
Q

What sections are found in the membranous labyrinth?

What do they do?

A

Semicircular Canals: Equilibrium
Utricle and Saccule: Acceleration
Cochlear Duct: Hearing
Sensory Cells

32
Q

What is kinocilium?

A

Specialized hair cells that can be displaced and result in depolarization or hyper polarization of the hair cells

33
Q

What are the three sections of the Cochlear Duct?

What lymph does each section contain?

A
  1. Scala Vestibule - Perilymph
  2. Scala Media - Endolymph
  3. Scala Tympani - Perilymph
34
Q

What makes up the roof and floor Scala Media?

A

Roof: Vestibular Membrane
Floor: Basilar Membrane

35
Q

What is found in the Basilar membrane?

A

Organ of Corti

36
Q

What is Organ of Corti composed of?

A

Hair cells (sensory)
Support Cells
Pillar Cells

37
Q

What is the ratio of outer hair cells to inner hair cells?

A

3:1

38
Q

Where is stereocilia found?

A

Overlying tectorial membrane, which is extending from spiral lamina

39
Q

What is the function of the external ear?

A

Directs sound waves to external auditory meatus

40
Q

What is the function of the middle ear?

A
  1. Takes sound waves and turns them into physical energy that pushes against auditory ossicles and then pushes on the oval window
  2. Controls pressure in the middle ear via Pharyngotympanic Tube
41
Q

What is the function of the inner ear?

A
  1. Transform sound waves to the brain

2. Balance

42
Q

How does sound move in the inner ear?

A
  1. Stapes moves oval window, causing the perilymph to change pressure in Scala Vestibule.
  2. This disturbs endolymph in scala media and displaces basilar membrane.
  3. Stereocilia in hair cells is distorted. Organ of Corti cells are distorted and initiates a signal via CN VIII.
  4. Perilymph in Scala Tympani takes the pressure and it exits via round window.
43
Q

What are the three canals in the semicircular canals and what is their axis?

A

Anterior: Sagittal Plane
Lateral: Transverse Plane
Posterior: Coronal Plane

44
Q

What is displaced by fluid motion within semicircular canal?

A

Cupulla: has hair cells with stereocilia

45
Q

What covers hair cells in the vestibule?

A

Otolithic Membrane

46
Q

What does the utricle sense?

A

Horizontal Acceleration

47
Q

What does the saccule sense?

A

Vertical Acceleration

48
Q

Where is perilymph drained to?

A

Subarachnoid Space

49
Q

Where is endolymph drained to?

A

Venous Sinuses of Dura Mater

50
Q

How does elastic cartilage get its nutrients?

A

Periochondrium

51
Q

What pathologies are associated with external ear?

A

Cauliflower Ear

Wrestling

52
Q

What is mastoiditis?

A

Infection of mastoid cells that can spread into cranial fossa

53
Q

How can the tympanic membrane be damaged?

A
  1. Medial Ear pressure from fluid

2. External Trauma

54
Q

What is Otitis Media?

A

Infection of the middle ear (can be viral, bacterial, fungal, etc). The ear is filled with fluid or pus.
Tympanic membrane is red and bulged

55
Q

What is Ménière’s Syndrome?

A

Increased endolymph that leads to abnormal signaling.

Can cause dizziness, vertigo, and possible hearing loss

56
Q

What can cause conductive hearing loss?

A

Problems with outer or middle ear

57
Q

What can cause sensorineural hearing loss?

A

Damage to inner ear or auditory nerve

58
Q

What can cause central hearing loss?

A

Problems in CNS

59
Q

Why do young children suffer from otitis media more than adults?

A

Pharyngotympanic tube is at a more shallow angle, allowing for less drainage and pressure equalization of the inner ear