Anatomy slides final review Flashcards
master (102 cards)
1
Q
At which end of the cochlea is the BM the narrowest and most tense
A
Basal end
2
Q
The 3 devisions of the cochlear nuclei are what?
A
DCN
AVCN
PVCN
3
Q
What are the 2 cochlear stimulus-related potentials?
A
Cochlear microphonic - AC potential which minics the stimulus
Summating potential - DC potential
4
Q
Name the 3 membranous structures in the vestibular system
A
Semicircular ducts
utricle
saccule
5
Q
What are the 4 bones comproising the temporal bone
A
Squamous
petrous
tympanic
mastoid
6
Q
What structures is on the immediate inner side of the spiral ligament
A
Stria vascularis
7
Q
What is the name of the tube that ventilates and drains the middle ear space
A
Eustachian OR auditory tube
8
Q
What is the inner ear fluid that has a high concentration of potassium and low concentration of sodium
A
Endolymph
9
Q
For vestibular hair cells, shearing toward the kinocilium has what action?
A
Excitatory - depolarization
10
Q
The 2 basic classes of theories of hearing are _________ and ________
A
Place (resonsance) theory
Temporal (frequency) theory
11
Q
What is the name of the medial wall of the middle ear space
A
Labyrinthine wall
12
Q
What is the resonant frequency of the average adult ear canal
A
Approximately 3400Hz
13
Q
In the vestibular system, type II hair cells have what shape
A
Test tube shape
14
Q
Which of the cranial nerves innervates tensor tympani
A
V - Trigeminal nerve
15
Q
What is the source and voltage of the endocochlear potential
A
Produces by the stria vascularis
voltage: +80 to +100 mV
16
Q
What are the 3 factors involved in the ME impedance matching function?
A
Areal ration of TM to OW
Pressure = F/area, so force at OW is increased 17 times
Lever action of ossicles
articulation of ME bones increases force and decreases velocity for an increase in the Z ratio of about 1.3
Buckling of TM
increases pressure about 2x
17
Q
The osseous structures in the vestibular system are the ______ and _______
A
Semicicular canals
vestibule
18
Q
Describe the 2 types of connections in the CC
A
Homolateral and Heterolateral
Homo: one place in one hemisphere to same place in the other hemisphere
hetero: connect different places in each hemispehre
19
Q
What is the fluid contained in Scala Vestibuli
A
Perilymph
20
Q
What is the anatomical term meaning “toward the bottom”?
A
Inferior
21
Q
The gelatinous structure in the semicircular canals into which the sterocilia are embedded is what?
A
cupula
22
Q
What is the section that divides the body into anterior and posterior parts?
A
Coronal
23
Q
What are the 2 major auditory nuclei of the LL
A
VNLL - monaural sound identification
DNLL - binaural sound localization
24
Q
What is the name of the fluid contained in scala media
A
endolymph
25
which of the vestibular hair cells is surrounded by an afferent terminal (calyx)
Type I cells
26
What is the direction of the BM traveling wave?
Why does it move that way?
The traveling wave always moves from base to apex
this is because of the changing mass and stiffness characteristics of the BM from base to apex
27
The bony prominence on the medial wall of the ME is known as what?
promontory
28
The two crucial functions of the SOC are
Sound localization; mediation site for the acoustic reflex
29
What structure is formed by the tops of the hair cells, phalangeal processes of support cells, and the pillar cells?
Reticular lamina
30
What is the cochlear fluid with a high concentration of sodium and a low concentration of potassium
perilymph
31
The hair cell with a test tube shape is the ______
Outer hair cell
32
How do the semicircular canals on each side of the head operate?
The canals operate in opposition to each other:
Horizontals work oppositely, and the left posterior and right anterior (and vice-versa) work oppositely
33
What is the name of the bony core of the cochlea
modiolus
34
Describe the blood supply to the cochlea
cochlear blood supply proceeds from the labyrinthine (internal auditory) artery
The labrinthine artery is a branch of the anterior inferior cerebellar artery (a branch of the basilar artery)
Venous drainage is through the internal auditory vein
35
What is the name of cranial nerve X?
Vagus
36
What are the 3 parts of a nerve cell
Dendrites
Soma (cell body)
Axon
37
What is the name of the membrane that separates scala media from scala vestibuli?
reissner's membrane
38
Describe the polarization directions of the otolith organs
Hair cell polarization in the saccule is away from the striola (line of polarity)
while polarization in the utricle is toward the stiola
39
What are neural tuning curves?
Tuning curves plot neural discharge rate as a function of frequency
they are a plot of the minimum stimulation level (across frequency) that brings about an increase in firing above the spontaneous rate (i.e. neural threshold of the fiber across frequency)
40
The thalamic auditory relay center is known as what?
MGB
41
What are the 3 effects of the outer ear on hearing
Protection of middle and inner ear structures
enhancement of mid and high frequencies
improved directional hearing
42
What are the 2 cell types in the organ of corti?
sensory cells - inner and outer hair cells
supporting cells - claudius, hensens, deiters, pillar, border, sulcus, and phalangeal cells
43
What is the role the olivocochlear bundle is belived to play?
Improving detection in noise protecting against noise damage
expanding the dynamic range improving auditory attention
44
The primary auditory cortex is located where?
On the superior surface of the superior temporal gyrus
(heschl's gyrus)
45
The grooves and ridges which can be used as landmarks on the cerebrum are known as what?
Sulci (grooves)
Gyri (ridges)
46
What membrane separates scala media from scala tympani?
BM
47
List the major nuclei of the ascending auditory pathway
CN
SOC
IC
MGB
PAC
48
Head rotaion along the X,Y, and Z axes are referred to as what?
X - roll
Y - pitch
Z - yaw
49
Describe the tectorial membrane, including its connections
The tectorial membrane is a gelatinous structure (about 95% water) which overlies the organ of corti
it is tightly connected to the limbus on the medial edge and loosely connected to the tops of the hensen's cells on the lateral edge
50
Which of the nuceli in the SOC is largest in humans
MSO
51
What is the name of the stucture which attaches the cochlear duct to the bony outer wall of the cochlea
Spiral ligamnet
52
What happens when the inner hair cells are activated
neurotransmitters are released
53
Name the 3 chambers of the middle ear space
Tympanic cavity
Epitympanic recess
Mastoid antrum
54
How many inner and outer hair cells are there in the human ear
There are about 3500 IHC
About 12,500 OHC
55
What is the name of the structure that is seated on the BM
organ of corti
56
What is the name of the muscle that is attached to the manubrium of the malleus?
TT
57
The otolith organ responsible for movement in the horizontal plane is what?
Utricle
58
What are the 2 cochlear resting potentials
Intercellular potential
-40 mV for IHC
-70 mV for OHC
Endocochlear potential
+80 to 100 mV
59
Which of the hair cells has a flask shape
IHC
60
The auditory central nervous system is organized into two major paths, which are what?
Sound localization
Sound Identification
61
What is the relationship between spontaneous neural discharge rate and threshold level?
Neurons with high spontaneous rates have lower thresholds and neurons with low spontaneous rates have higher thresholds
62
The principle (although not sole) generator of wave V of the ABR is what?
LL
63
The hair cell bodies are bathes in ________, while the stereocilia are bathes in ________
perilymph
Endolymph
64
The major descending projection of the central auditory system is what?
Olivocochlear system which projects from the SOC to the cochlea
65
What os the name of the gelatinous structure that overlies the hair cells?
Tectorial membrane
66
The stucture which lies ddeep within the lateral suclus and connects to both the primary auditory and association areas (and is believed to play a variety of roles in aduitory processing) is known as what?
insula
67
What are the landmarks of the auricle 7
Helix
Antihelix
Tragus
Antitragus
Triangular Fossa
Concha
Lobule
68
About how many primary auditory neurons are in the human ear?
How many of these are afferent?
30,000 primary auditory neurons in the human ear
95% are afferent
69
The two sections of the BM are known as what
Zona arcuata
Zona pectinata
70
Describe the tonotopic organization of the auditory branch of CN VIII
Fibers innervating the apical hair cells form the center of the bundle while fibers innervating the basal hair cells form the outside of the bundle
71
What is the term that describes the frequency to place oragnization seen in the auditory system
tonotopy or tonotopic organization
72
What do we call collections of nerve fibers and cell bodies in the periphery and the central nervous system?
Nerves in the periphery are made up of nerve fibers or neruons
in the central nervous system, a collection of nerve fibers is called a tract
A collection of cell bodies in the periphery is called a ganglion
A collection of cell bodies in the CNS is called a nucleus
73
A neuorn identified as EI is one that has what stimulation
Excitatory input from the contralateral ear and inhibitory input from the ipsilateral ear
74
What are the names of the 2 sections of the tympanic membrane
pars tensa (3-4 layers)
Pars flaccida (2 layers)
75
Describe the two different types of afferent primary auditory neurons
About 95% of the afferent fibers are type I; these are large, myelinated bipolar neurons which contact the IHC
The remaining 5% of fibers are type II; these are small unmyelinated pseudo-monopolar neurons which contact the OHC
76
What happens when the medial olivocovhlear bundle is stimulated?
When the MOC is stimulated, the activity of the OHC is inhibited, so that sensitivity and tuning are reduced
77
Which of the cranial nerves innervates the stapedius muscles?
VII - facial nerve
78
Which of the 3 nuclei of the IC is responsive to auditory stimuli?
The 3 nuclei are the central (ICC), external (lateral) cortex, and the dorsal cortex
The ICC is the specific, core or lemniscal nucelus, which is responsive to sound.
The external cortex and dorsal cortex are the diffuse, belt or non-lemniscal nuclei, which integrate the auditory and non-auditory inputs
79
What is the primary generator of the cochlear microphonic
OHC
80
What is the name of the process in which the sterocilia of the hair cells are activated by the tectorial membrane?
Shearing
81
Describe the arcs of the acoustic reflex there are 2 ipsi 2 contra
- In one ipsilateral arc, the primary neuron projects to the ventral cochlear nucleus, the secondary neuron projects through the trapezoid body to the ipsi facial nerve nucleus, and the 3rd order neuron projects from the facial nerve nucleus to the ipsi stapedius
- In the other ispilateral arc, the primary neuron projects to the VCN, the secondary neuron projects to the ipsi SOC, the 3rd order neuron projects to the ipsi facial nerve nucleus, and the 4th order neuron projects to the ipsi stapedius
Contralateral Arcs:
- In one contralateral arc, the primary neuron projects to the ipsi VCN, the secondary neuron projects to the ipsi SOC, the 3rd order neuron projects to the contralateral facial nerve nucleus, and the 4th order neuron projects to contra stapedius
- In the other contralateral arc, the primary neuron projects to the ipsi VCN, the secondary neuron projects to the contra SOC, the 3rd order neuron projects to the contra facial nerve nucleus, and the 4th order neuron projects to the contra stapedius
82
The breaks in the myelin sheath along the neurons axon are known as what?
Nodes of ranvier
83
Describe the composition and linkages of the stereocilia?
Stereocilia are composed of actin filaments, which are cross-linked and tip-linked
The Tip-link play an important role in the transduction process
84
The hair cells of the otolith organs are located in what?
Maculae
85
What happens when the outer hair cells are "activated"
The OHCs become motile which "sharpens" the traveling wave, improving sensitivity and frequency resolution
86
Name the 3 middle ear bones
Malleus
Incus
Stapes
87
What is the name of the muscle that is attached to the stapes?
Stapedius
88
Name the cranial nerves
I. Olfactory
II. Optic
III. Oculomotor
IV. Trochlear
V. Trigeminal
VI. Abducens
VII. Facial
VIII. Vestibulocochlear
IX. Glossopharyngeal
X. Vagus
XI. Accessory
XII. Hypoglossal
89
What are the voltages of the intracellular resting potentials
The resting potential of the IHC is approx. -40 mV
And the resting potential of the OHC is approx. -70 mV
90
What do auditory neuron studies tell us about the auditory system and hearing
1. Intensity is rate-coded
2. Auditory nerve fibers are tuned in frequency
3. Neural Discharge patterns are "phase-locked" for frequencies below about 4000-5000 Hz
91
What is the position of the manubrium of the malleus when viewing the right ear through an otoscope
Pointing toward 1 O'Clock
92
Describe the vestibulo-Ocular reflex
To maintain gaze, the VOR produces compensatory eye movements of the same magnitude, but opposition in direction, to the movement of the head
93
What are the major cues to localization in the horizontal plane?
Frequencies below 1900 Hz are diffracted, so cue is difference in interaural time of arrival
For frequencies above 1900 Hz , cue is interaural level difference
94
Describe Cranial Nerve VIII
Known as the auditory or vestibulocochlear nerve
Made up of 2 branches - 1 arising from the vestibular system and 1 from the cochlea
The afferent fibers innervate the hair cells and carry information toward the central system
The cell bodies of these neurons make up the spiral ganglia
The efferent fibers are the terminations of the olivocochlear bundle.
Most of the neurons in the vestibulocochlear nerve are bipolar
95
What is the name of the ligament that supports the stapes footplate in the oval winow
Annular ligament
96
What happens when the sterocilia of the hair cells are sheared?
Ions flow into the cells
97
Neurons may be classified in three groups. These are _________
Sensory
Motor
Interneurons
98
Damage to the synaptic junction between the hair cells and the auditory nerve results in
The condition known as synapotopathy or "hidden hearing loss" becasue it does not elevate thresholds, but rather is associated with problems on more omplex auditory tasks, such as speech recognition in noise
99
Name the eye muscles
Superior rectus muscle
Inferior rectus muscle
Lateral rectus muscle
Medial rectus muscle
Superior oblique muscle
Inferior Oblique muscle
100
Name the 3 channels of the inner ear
Scala Vestibuli
Scala Media
Scala Tympani
101
What is the resonant frequency of the middle ear?
1200 Hz
102
Idetify stuctures of the organ of corti
