3: Anatomy 2 - ear Flashcards
1
Q
Which bone protects the organs of hearing and balance?
A
Temporal bone
2
Q
What kind of nerve fibres innervate the ear?
A
Special sensory nerves
3
Q
Which cranial nerves are most responsible for hearing and balance?
A
CN VII (Facial nerve)
CN VIII (Vestibulocochlear nerve)
4
Q
What is the pterion?
A
Intersection of the
FRONTAL, PARIETAL, TEMPORAL and SPHENOID sutures
also the thinnest part of the skull
5
Q
What is the thinnest part of the skull and which bone is it found on?
A
Pterion
Temporal bone
6
Q
What is the lower part of the temporal bone called and why?
A
Petrous part
harder than the upper part
7
Q
What part of the temporal bone forms the outer opening of the ear?
A
External acoustic meatus
8
Q
What is the pointy projection at the lower part of the temporal bone which can be palpated behind the ear?
A
Mastoid process
9
Q
What is the thin projection from the temporal bone which acts as the insertion for some muscles of the tongue and pharynx?
A
Styloid process
10
Q
Which process attaches the temporal bone to the zygomatic bone?
A
Zygomatic process
11
Q
What are the three important processes of the temporal bone?
A
Mastoid process
Styloid process
Zygomatic process
12
Q
Which bone forms the hard palate?
A
Palatine bone
13
Q
Which bones make up the floor of the anterior cranial fossa?
A
Frontal, ethmoid and sphenoid bones
14
Q
Which bones make the floor of the middle cranial fossa?
A
Sphenoid and temporal bones
15
Q
Which bones make up the floor of the posterior cranial fossa?
A
Temporal and occipital bones
16
Q
Do the parietal bones make up the floors of any cranial fossa?
A
No (found on the walls)
17
Q
Where does CN I exit the cranial cavity?
A
Cribriform plate
18
Q
Where does CN II exit the cranial cavity?
A
Optic canal
19
Q
Where do CN III, IV, V1 and VI exit the cranial cavity?
A
Superior orbital fissure
20
Q
Where does CN V2 exit the cranial cavity?
A
Foramen rotundum
21
Q
Where does CN V3 exit the cranial cavity?
A
Foramen ovale
22
Q
Where do CN VII and VIII exit the cranial cavity?
A
Internal acoustic meatus
23
Q
Where do CN IX, X and XI exit the cranial cavity?
A
Jugular foramen
(so does the internal jugular vein)
24
Q
Where does CN XII exit the cranial cavity?
A
Hypoglossal canal
25
What are the **three** general parts of the ear
**External ear**
**Middle ear**
**Internal ear**
26
The **external ear** goes from the ___ to the ___ \_\_\_.
**auricle**
**tympanic membrane**
27
What joins the auricle to the external tympanic membrane?
**External acoustic meatus**
28
What is the purpose of the external ear?
**Collects sound waves and conveys them to tympanic membrane**
29
The **middle ear** goes from the ___ \_\_\_ to the ___ \_\_\_.
**tympanic membrane**
**oval window**
30
Apart from the tympanic membrane, ossicles and oval window, what other important structure is found in the **middle ear**?
**Eustachian tube**
31
What is the purpose of the **middle ear**?
**Amplifies sound**
32
The **internal ear** goes from the ___ \_\_\_ to the ___ \_\_\_ \_\_\_.
**oval window**
**internal acoustic meatus**
33
What is the purpose of the **internal ear**?
**Turns sound waves into action potentals**
34
What is the **external ear** called?
**Auricle**
35
What is the **posterior outer rim** of the ear called?
**Helix**
36
What is the **rim of the ear** next to the **external acoustic meatus** called?
**Tragus**
37
Which nerves supplies sensory fibres for most of the **posterior helix?**
What is the exception?
**C2** and **C3**
Tiny bit by **CN VII**
38
Which cranial nerve supplies most of the inner helix and the external acoustic meatus?
**CN V3** - mandibular division
39
Which two cranial nerves supply the **external acoustic meatus** with sensory fibres?
**CN V3**
**CN X**
40
Which lymph nodes drain the **superior half of the auricle** (facing forward)?
**Parotid lymph nodes**
41
Which lymph nodes drain the **superior half** of the auricle (facing posteriorly)?
**Mastoid lymph nodes**
42
Which lymph nodes drain the lower half of the auricle and the ear lobe?
**Superficial cervical nodes**
43
Where does all lymph from the auricle eventually drain?
**Deep cervical lymph nodes**
44
The **external ear** is made out of the **temporal bone** and elastic \_\_\_.
**cartilage**
45
What is the technical name for the **ear canal**?
**External acoustic meatus**
46
Which type of gland produces **earwax** in the **external acoustic meatus**?
**Ceruminous glands**
47
What name is given to a medical device used to look inside the ear?
**Otoscope / auriscope**
48
In a child, what shape is the **external acoustic meatus**?
**Short and straight**
49
In an **adult**, what shape is the **external acoustic meatus**?
**Curved**
50
What structure do you want to look at with an **otoscope**?
**Tympanic membrane**
51
What are some important structures of the tympanic membrane?
**Umbo** (depressed part)
**Pars flaccida** (thin, superior part)
**Pars tensa** (thick, inferior part)
52
Which **cranial nerves** supply **sensory fibres** to the
a) **external**
b) **internal** surfaces of the tympanic membrane?
**a) CN V3** - mandibular division
**b) CN IX** - glossopharyngeal nerve
53
What areas of the head and neck does **CN IX** supply?
**Middle ear**
**Eustachian tube**
**Nasopharynx**
**Oropharynx**
**Tonsils**
54
CN __ supplies the **middle ear, eustachian tube, nasopharynx** and **oropharynx** with sensory nerve fibres.
**CN IX**
55
What is the collective name for the **three bones** of the inner ear?
**Auditory ossicles**
56
What are the **three auditory ossicles** called?
**Malleus** (mallet)
**Incus** (anvil)
**Stapes** (stirrup)
57
Which auditory ossicle looks like an anvil?
**Incus**
58
Which auditory ossicle looks like a mallet?
**Malleus**
59
Which auditory ossicle looks like a stirrup?
**Stapes**
60
Which type of joint connects **malleus, incus** and **stapes**?
**Synovial joint**
61
What creates the **umbo** of the tympanic membrane?
**Handle of the malleus** pressing on it
62
What space is found **superior** to the tympanic membrane?
**Epitympanic recess**
63
What space is found **posterior** but not **inferior** to the tympanic membrane?
**Tympanic cavity**
64
Which tube is found in the tympanic cavity and connects the middle ear to the nasopharynx?
**Eustachian tube**
65
Which cranial nerve supplies the middle ear **and** the nasopharynx?
**CN IX**
66
Why can **pharyngitis** or **tonsilitis** cause earache?
**Referred pain** as **CN IX supplies both areas**
67
Apart from the eustachian tube, what other structure in the epitympanic recess is a tube which connects to the **mastoid antrum**?
**Aditus**
68
Through which structure does the **facial nerve** travel to the **stylomastoid foramen**?
**Internal acoustic meatus**
**Facial canal**
69
Where in the brainstem does the **facial nerve** arise?
**Pons-medullary junction**
70
Which cranial bone is the **internal acoustic meatus** found in?
**Temporal bone**
71
The facial nerve travels through the **internal acoustic meatus** and **facial canal** before emerging where?
**Stylomastoid process**
72
Which tube connects the **internal acoustic meatus** to the **stylomastoid process**?
**Facial canal**
73
What is a **branch** which comes off the facial nerve?
What does it supply?
**Chorda tympani**
**Taste** to anterior 2/3rds tongue
**Parasympathetics** to **submandibular and sublingual glands**
74
The **facial nerve** innervates a muscle which stops the **stapes** from vibrating too much - what is it called?
**Stapedius**
75
What are the **functions** of the facial nerve?
**PARASYMPATHETIC** - lacrimal, submandibular and sublingual glands
**SOMATIC MOTOR** - muscles of facial expression
**SOMATIC SENSORY** - tiny part of auricle
76
Which other cranial nerve does the **chorda tympani** hitch a ride with to reach the submandibular and sublingual glands?
**CN V3**
Lingual nerve
77
What are some of the **muscles of facial expression**?
**Frontalis**
**Orbicularis oculi**
**Lip elevators**
**Orbicularis oris**
78
How can the **motor** function of **CN VII** be tested?
**Ask patient:**
frown
close eyes tightly
smile
puff out cheeks
79
Which ganglion do lots of CN VII fibres **synapse** at in the facial canal?
**Geniculate ganglion**
80
Which part of the ear is responsible for turning sound waves into action potentials?
**Internal ear**
81
Which **cranial** **nerve** is responsible for **hearing** and **balance?**
**CN VIII** - Vestibulocochlear nerve
82
Which **parts** of **CN VIII** are responsible for
a) hearing
b) balance?
**a) Cochlear nerve**
**b) Vestibular nerve**
83
The **vestibular nerve** is responsible for \_\_\_.
The **cochlear nerve** is responsible for \_\_\_.
**balance**
**hearing**
84
Through which structure do CN VIII fibres travel to the brain?
**Internal acoustic meatus**
85
What is the complicated structure found in the **internal ear** which contains the **cochlea** and **semicircular canals**?
**Otic capsule**
86
What are the **spaces** within the otic capsule called?
**Labyrinths**
87
What are the **two** labyrinths found within the otic capsule?
**Bony labyrinth**
**Membranous labyrinth**
88
The ___ labyrinth is found within the ___ labyrinth.
**membranous** WITHIN **bony**
89
What kind of fluid is found within the
a) **bony**
b) **membranous** labyrinths?
**a) Perilymph**
**b) Endolymph**
90
What fluid allows the **membranous labyrinth** to float within the **bony labyrinth**?
**Perilymph**
91
Which structure of the otic capsule looks like a snail's shell?
**Cochlea**
92
What is the **apex** of the cochlea called?
**Cupula**
93
Which nerve travels in the **cochlea**?
What is it responsible for?
**Cochlear nerve**
**Hearing**
94
What are the long balloon-like structures which contain **endolymph** and the **vestibular nerve**?
**Semicircular canals**
95
What is the **path** of soundwaves in the internal ear?
**1. Sound wave vibrate tympanic membrane**
**2. Auditory ossicles vibrate**
**3. Stapes vibrates the oval window**
**4. Pressure waves in PERILYMPH activate HAIR CELLS**
**5. Hair cells release neurotransmitters and an action potential is conveyed to the brain by the cochlear nerve**
**6. Round window DAMPENS pressure waves**
96
What are the two windows found in the otic capsule?
What are they for?
**Oval window** and **round window**
Oval window is where the stapes vibrates and triggers a pressure wave
Round window is where the leftover pressure wave is dampened after an action potential has been generated
97
Where do **CN VII** and **CN VIII** connect to the brainstem?
**Pons-medullary junction**
98
The **cochlear nerve** and therefore hearing is controlled by the **(cochlea / semicircular canals)**.
**cochlea**
99
The **vestibular nerve** and therefore balance is controlled by the (**cochlea / semicircular canals**).
**semicircular canals**
100
If you had an **acoustic neuroma** (tumour in the internal acoustic meatus) what symptoms would be produced on behalf of
a) **CN VII**
b) **CN VIII**?
**a) Loss of function of muscles of facial expression, dry eyes** (reduced lacrimation), **dry mouth** (reduced submandibular / sublingual secretions)**, loss of sensation at that little bit of the auricle, loss of taste**
## Footnote
**b) Loss of hearing, loss of balance**
