Anatomy of the Ear Flashcards Preview

ESA 4 - Head and Neck > Anatomy of the Ear > Flashcards

Flashcards in Anatomy of the Ear Deck (97)
Loading flashcards...
1
Q

What is the ear?

A

The organ of hearing and balance

2
Q

Where is the ear found?

A

Within the petrous part of the temporal bone

3
Q

What does the petrous part of the temporal bone constitute?

A

\A large portion of the lateral area of the skull

4
Q

What does the petrous part of the temporal bone house?

A

The cavities of the ear

5
Q

What are the components of the temporal bone?

A
  • Squamous part
  • Petromastoid part
  • Tympanic plate
  • Styloid process
6
Q

What does the petromastoid part of the temporal bone contain?

A

The middle and inner ear

7
Q

What does the upper surface of the petromastoid part of the bone form?

A

Part of the floor of the middle and posterior cranial fossae

8
Q

What is the part of the petromastoid part that forms the posterior cranial fossa is pierced by?

A

The internal acoustic meatus

9
Q

What does the internal acoustic meatus transmit?

A

Facial and vestibulocochlear cranial nerves

10
Q

Describe the inferior surface of the petromastoid part of the temporal bone?

A

Irregular

11
Q

What does the inferior surface of the petromastoid part of the temporal bone contain?

A

The carotid canal

12
Q

What is the purpose of the carotid canal?

A

Transmits the internal carotid artery

13
Q

What is the mastoid process?

A

A large palpable landmark to which several muscles are attachedf

14
Q

What is the cavity of the mastoid antrum?

A

A prolongation of the cavity of the middle ear

15
Q

What extends into the mastoid process?

A

The cavity of the mastoid antrum, by intercommunicating air cells

16
Q

What is the clinical significance of the communication between the mastoid antrum and the mastoid process?

A

Middle ear disease can spread by this route to cause mastoiditis

17
Q

What does the tympanic plate consist?

A

Most of the external acoustic meatus

18
Q

What does the free outer border of the tympanic plate do?

A

Provides attachment for the cartilage of the external ear

19
Q

What does the tympanic plate do medially?

A

Fuses with the petrous part of the temporal bone

20
Q

What does the external ear consist of?

A
  • Pinna/auricle
  • External acoustic meatus (ear canal)
  • Lateral surface of tympanic membrane
21
Q

What is the functional of the external ear?

A

Collects, transmits, and focuses sound waves onto the tympanic membrane

22
Q

What does the action of the external ear on the tympanic membrane cause?

A

The membrane to vibrate

23
Q

Draw a picture of the pinna/auricle

A
24
Q

Describe the pinna

A

Cartilaginous and covered with skin

25
Q

What is true of the elastic cartilages of the pinna?

A

They are arranged in a number of curved ridges

26
Q

What is the outer rim of the ear called?

A

The helix

27
Q

What is the small flap of cartilage of the ear called?

A

The tragus

28
Q

What does the tragus do?

A

Guards the external acoustic meatus

29
Q

What is the earlobe?

A

A fatty structure

30
Q

What is the external acoustic meatus?

A

A skin-lined cul-de-sac

31
Q

What shape is the external acoustic meatus?

A

Sigmoid shape

32
Q

What is the clinical relevance of the sigmoid shape of the external acoustic meatus?

A

Need to pull ear up and back to straighten when examining

33
Q

How long is the external acoustic meatus?

A

2.5cm

34
Q

Describe the external acoustic meatus

A
  • Outer 1/3 cartilaginous tube
  • Inner 2/3 bony canal
35
Q

Where does the external acoustic meatus lie?

A

In the temporal bone

36
Q

What is the external acoustic meatus lined by?

A

Skin

37
Q

What is the purpose of the self cleaning function of the external acoustic meatus?

A

Keep pathway clear

38
Q

What facilitates the self cleaning function of external acoustic meatus?

A

Arrangement of hairs and production of wax by the cartilaginous part

39
Q

What does the cartilaginous part of the external acoustic meatus secrete?

A

Cerumen

40
Q

What is cerumen?

A

Modified sebum

41
Q

What does cerumen do?

A

Affords protection to the delicate meatal skin

42
Q

What forms wax?

A

Discarded cells of the skin together with cerumen

43
Q

What is the function of wax?

A
  • Prevents objects entering deeper into the ear canal
  • Aids desquamation and skin migration out of canal
44
Q

How can the external ear be visualised?

A

An otoscope

45
Q

What does the fibrous tympanic membrane mark?

A

The border between the external and middle ear

46
Q

How is the tympanic membrane arranged?

A

As a shallow cone with its apex pointing medially

47
Q

Is the fibrous tympanic membrane transparent or opaque?

A

Neither, it is translucent

48
Q

What is the result of the tympanic membrane being translucent?

A

It allows visulisation of some structures within the middle ear, including the malleus

49
Q

What is attached to the malleus?

A

The apex of the eardrum

50
Q

What is the pars tensa?

A

The taut surface area of the tympanic membrane

51
Q

Draw a diagram of the tympanic membrane

A
52
Q

What is the result of the pars tensa being stretched?

A

It vibrates in relation to airwaves as they hit the eardrum

53
Q

What is the pars flaccida?

A

The loose connective tissue above the malleus

54
Q

What is the handle of malleus?

A

Where the first ossicle is attached to the tympanic membrane

55
Q

What does the middle ear, or tympanic cavity contain?

A

Ossicles

56
Q

What do ossicles do?

A

Transmit vibrations from the tympanic membrane to the inner ear in the petrous part of the temporal bone

57
Q

What are the names of the ossicles?

A
  • Malleus
  • Incus
  • Stapes
58
Q

What is the handle of the malleus attached to?

A

The tympanic membrane

59
Q

What does the body of the malleus articulate with?

A

That of the incus

60
Q

What does the incus articulate with?

A

Stapes

61
Q

What do the stapes articulate with?

A

The bony labyrinth of the internal ear

62
Q

Where does the stapes articulate with bony labyrinth of the internal ear?

A

At the oval window

63
Q

What are the articulations of the ossicles by?

A

Synovial joints

64
Q

What do the articulations of the ossicles of the ear serve to do?

A

Relay vibrations encountered by the tympanic membrane to the internal ear

65
Q

What is the function of the ossicles?

A

Amplify and concentrate sound energy from the eardrum to the oval window

66
Q

What does the oval window run into?

A

The epitympanic cavity

67
Q

What does the middle ear communicate with anteriorly?

A

The nasopharynx

68
Q

How does the middle ear communicate with the nasopharynx?

A

Via the pharyngotympanic (Eustachian) tube

69
Q

What is the Eustachian tube part of?

A

The upper respiratory tract

70
Q

What is the clinical relevance of the Eustachian tube?

A

It is a potential route for infection to spread to the middle ear

71
Q

What does the Eustachian tube allow for?

A
  • Equalisation of air pressure between middle ear and atmosphere
  • Important in ventilation and drainage of mucus from the middle ear
72
Q

What is the equilisation of air pressure between middle ear and atmosphere necessary for?

A

Transfer of sound energy to internal ear

73
Q

What state is the Eustachian tube usually in?

A

Closed

74
Q

How is the Eustachian tube intermittently opened?

A

By the pull of attached palate muscles when swallowing

75
Q

What does the middle ear communicate with posteriorly?

A

Mastoid air cells

76
Q

What is the inner ear also known as?

A

Labyrinth

77
Q

What does the inner ear consist of?

A

A series of channels hollowed out of the petrous temporal bone surrounding the membranous labyrinth

78
Q

What does the membranous labyrinth contain?

A

Fluid called endolymph

79
Q

What does the perilymph seperate?

A

The bony and membranous labyrinths

80
Q

What does the labyrinth contain?

A
  • Vestible
  • Semicircular ducts and canals
  • Cochlea
  • Spiral organ of Corti
81
Q

What is the vestible involved in?

A

Maintaining our sense of position and balance

82
Q

What does the vestible contain?

A
  • Utricle
  • Saccule
  • Three semicircular canals
83
Q

What do the utricle and saccule contain?

A

Receptors that respond to rotational acceleration and static pull of gravity

84
Q

What are the semicircular ducts and canals?

A

Components of the balance system

85
Q

What does the semicircular ducts and canals communicate with?

A

Vestible

86
Q

How are the semicircular ducts and canals arranged?

A

Perpendicular with each other

87
Q

What do the semicircular ducts and canals contain?

A

Receptors that respond to rotational acceleration in three different planes

88
Q

What is the cochlea?

A

A fluid filled tube

89
Q

What sets up movements of fluid into the coclear?

A

Movements at the oval window

90
Q

What do waves of fluid cause in the cochlea?

A

Movement of special sensory cells within the cochlear duct which fire action potentials

91
Q

What is the cochlea the clinical site of?

A

Sensorineural hearing loss

92
Q

What does the cochlear contain?

A

The cochlear duct

93
Q

What does the cochlear duct accommodate?

A

The spiral organ of Corti

94
Q

What is the cochlear concerned with?

A

Hearing

95
Q

How is the cochlear duct associated with hearing?

A

It converts sound vibration into electrical signals (action potentials) which is perceived as sound

96
Q

What does the spiral organ of Corti contain?

A

The receptors of the auditory apparatus

97
Q

How is vibration created by sound waves at the tympanic membrane translated into electrical signal in the vestibulocochlear nerve?

A
  1. Vibration of the ossicles (stapes at the oval window) sets up vibrations/movement in the cochlear fluid
  2. Sensed by nerve cells in the cochlear duct (part called the spiral organ of Corti)
  3. Movement of these receptors in organ of Corti trigger action potentials in CN VIII

Go to brain