9. Anatomy of Hearing Flashcards
Components of the Outer Ear
Temporal Bone
Left Cochlea
Brain
Hearing system is a
transducer
What energies are involved in the hearing system? What is the relation?
Acoustic and electrochemical energy
Transducting: acoustic energy is converted into electrochemical energy
Temporal bone contains
middle and inner ear
Audition
process associated with hearing
Transduction
ear converts acoustic energy into electrochemical energy
Auditory mechanism
inner ear
middle ear
outer ear
auditory pathway
Outer ear aka
pinna aka auricle
Components
Helix Antihelix Concha Scaphoid Fossa Crura Anthelicis Trianglualr Fossa
Role of Outer Ear
collects sound; localizes sound in space; captures sound energy
Parts of Concha
Concha Auriculae
Cymba Conchae
Cavum Conchae
Exterior area of ear
Targus
Antitargus
Intertragic Incisure
Lobule (Lobe)
Ear Canal
External Auditory Meatus (EAM)
EAM
External Auditory Meatus aka Ear Canal
EAM is ____ -shaped
S
How much of EAM is cartilage?
1/3 (lateral)
How much of EAM is temporal bone?
2/3 (medial)
Tympanic membrane (TM)
Ear Drum
Ear Drum
Tympanic membrane (TM)
What shape is the TM?
Oval
What are the three layers of tissue of the TM?
Cuticular layer
Fibrous layer
Mucous layer
Outer tissue layer of TM
Cuticular layer - continuation of epithelial lining of EAM and pinna
Intermediate tissue of TM
Fibrous layer
deep - circular fibers, periphery of membrane
superficial - fibers radiate out of handle of malleus to periphery
Inner tissue of TM
Mucous layer
continuous with mucosa of middle ear
Pars flaccida
superior to malleus
Manubrium malli
points of attachment exterior TM
Umbo
most distal attachement of manubrium
Cone of Light
Tensed membrane
Result of tension arising from attachment of manubrium to TM
Cone of Light
Middle Ear Cavity
houses middle ear ossicles
Medial wall of MEC
separates middle ear from cochlea
promontory of MEC
bulge from basal turn of cochlea
oval window of MEC
stapes footplate fits into space; lateral wall of vestible that links three osseous semicircular canals by apertures
lateral semicircular canal
part of vestibular system to determine position in space
shaking head “no”
body rotation
aeration
auditory tube brings in oxygen to middle ear (ONLY WAY)
Auditory tube
equalizes pressure differences between atmposphere and middle ear space
Auditory tube is connected to ______ in ____ and ____ orientation
nasopharynx
medially
anteriorly
Jugular bulb
underneath middle ear cavity floor
Interaction of these three canals allows brain to orient body’s position and orientation in 3D space
osseous semicircular canals
Anterior semicircular canal
side-to-side movement
head moving toward shoulders
posterior semicircular canal
nodding head yes
How does auditory system develop overall sense of rotation?
Anterior semicircular canal of one ear is parallel to posterior canal of other ear
ampulla
sensory organ for movement
inertia
responsible for stability and shape of canals
What structure houses the sensory organ for hearing?
Cochlea
What structure houses the sensory organs for balance?
Vestibular organ
The ___ of each semicircular canal houses the sensory mechanism for that canal
Ampulla
Cochlea
houses sensory organs for hearing
Cochlea coil makes just less(fewer) than ___ turns from base to apex
3
Modiolus
fibers of VIII vestibulocochlear nerve passes through perforation
Internal auditory meatus
VII facial nerve enters cranial activity
VIII vestibulocochlear nerve exits
temporal bone and enters cranial space
Vestibular organ
house sensory organs for balance
scala vestibuli
begins at vestibule and becomes inner part of spiral
how does scala vestibuli connect with middle ear space?
oval window
scala media
between vestibuli and tympani
endolymph
inner labyrinth fluid
perilympth
outer labyrinth fluid
Helicotrema
connects scala vestibuli and scala tympani
how does scala tympani connect with middle ear?
round window
The ___ of each semiciruclar canal houses the sensory mechanism of that canal
ampulla
Stapes footplate
fits in oval window and pushes on fluid
Fluid-filled sac rests within cavity of osseous labyrinth
Membranous labyrinth
Fluid within membranous labyrinth
endolymph
Fluid outside of the membranous labyrinth
perilymph
Houses sensory organ of each semicircular canal
ampulla
found in each ampulla
crista ampularis
overlays each crista ampularis
cupola
Many ___ protrude from each hair cell
sterocilia
One ___ protrudes from each hair cell
kinocilium
The ___ and ___ are within the membranous vestibule
saccule and utricle
what are the three bones in the ossicular chain?
Malleus
Incus
Stapes
which muscle looks like a hammer?
malleus
which muscle looks like an anvil?
incus
which muscle looks like a stirrup?
stapes
ossicles are ___ to the tympanic membrane
medial
produced by the articulation of the lateral process within the tympanic membrane
pars flaccida
forms articulation between malleus and incus
malleoincudal joint
point of articulation of incus and stapes
lenticular process
muscle arising from posterior wall of middle ear cavity
stapedius muscle
muscle that tenses tympanic membrane
tensor tympani muscle
efferent innervation of the hair cell is
inhibitory
rests atop the hair cells
tectorial membrane
organ of corti rests on
basilar membrane
Deiters’ Cells
bed that four rows of hair cells rest on
Where are inner and outer hair cells located?
organ of corti
How many cells and rows in inner hair cells?
one row; 3500 cells
how many cells and rows in outer hair cells?
three rows; 12,000 cells
“many-to-one” innervation
inner hair cell innervates as many as 10 VIII nerve fibers; “10 times as many votes”
“one-to-many” innervation
outer hair cells
Shares innervation with 10 other outer hair cells that are all innervated by SAME VIII nerve fiber
Reissner’s Membrane
separates scala vestibuli and scala media
Basilar Membrane
separation between scala media and tympani
osseus spiral lamina
medial attachment of membranous labyrinth
stria vascularis
distal side of scala media; highly vascularized labyrinth
cause excitation of hair cells in cochlea
Mechanical Processes
process of extracting info about frequency components of sound
Spectral Analysis
result of stimulation by mechanical processes
Electrochemical Processes
T or F: When the tympanic membrane moves inward, the stapes footplate in the oval window also moves in
True
T or F: Movement of the stapes footplate is a direct analog to the compressions and rarefactions of sound
True
T or F: When the Reissner’s membrane is distended away from the scala media
False
Reissner’s membrane moves toward scala media
Stimulation of basilar membrane results in
Traveling wave
Where in cochlea is high-frequency stimulation processed?
Base
T or F: The point of maximum amplitude excursion of the traveling wave on the basilar membrane is the primary point of excitation of the hair cells
True
The basilar membrane has ____ mass at the apex than at the base
more
The basilar membrane has ____ width at the apex than at the base
more
The basilar membrane has ____ stiffness at the apex
less
T or F: The shearing relationship between the tectorial membrane and outer hair cells causes the cilia to bend
true
T or F: The shearing relationship between the tectorial membrane and the inner hair cells causes the cilia to bend
False
CNS
Central Nervous System
Brain and Spinal cord
PNS
Peripheral Nervous System
12 pairs of cranial nerves
31 pairs of spinal nerves
Sensory receptors
Parts of neuron
Axon, Terminal bouton, Dendrites, Soma, Synapse
Types of neurons
Interneurons
Motor neurons
Sensory neurons
Efferent pathway
Motor neurons
info passes from cortex to other regions
Afferent pathway
Sensory neurons
info concerning body state passes to brain or brain centers
Speeds up rate of conduction of neuron
Myelin
Areas in which myelin is missing
Nodes of Ranvier
Body of neuron
Soma
Reside within terminal end button of neuron
Synaptic Vesicles
Found within synaptic vesicles
Neurotransmitter
Neurotransmitter substances released into
Synaptic cleft
Motor neurons
Efferent neurons
Information generally exits through the
Axon
Information is generally received at the
Dendrites
Sensory neurons
Afferent neurons
Corpus callosum is made up of ____ fibers
Commissural
____ fibers connect one location on hemisphere with corresponding location on other hemisphere
Commissural
____ connect cerebrum with distant structures
Projection Fibers
Connect neurons of one gyrus to the next, traversing the sulcus
Short Association Fibers
Interconnect lobes of brain within same hemisphere
Long Association Fibers
Arcuate fasiculus is example of group of
Long Association Fibers
Most superficial lining of brain
Dura mater
Lacelike covering through which many blood vessels for brain pass
Arachnoid mater
Inner-most layer of meinges
Pia mater
Inside each ventricle of CSF is ____ which produces cerebrospinal fluid
choroid plexus
Largest of ventricles of CSF and are found in each lobe of cerebrum
lateral ventricles of CSF
Passageway between lateral ventricles and 3rd ventricles of CSF____
foramen of monro
Medial cavity between left and right thalami
3rd ventricle of CSF
3rd ventricle is connected fo 4th ventricle by means of (ventricles of CSF)
cerebral aqueduct
situated behind pons and medulla
4th ventricle of CSF
CSF
Cerebrospinal Fluid
Area of brain critical for coordination of movement
Cerebellum
Final sensory relay for sensory info conducted to cerebrum
Thalamus
Regulates reproductive behavior and physiology and desire for food and water
Hypothalamus
Damage to ____ will result in movement deficit
Basal Ganglia
Area in brain responsible for highest cognitive function of self reflection
Dorsolateral Prefrontal Cortex
Motor act rehearsal and response inhibition
Supplementary Motor Area
Execution of simple motor function
Precentral Gyrus
Execution of complex motor acts as well as planning
Premotor Gyrus
Broca’s Area
Where expressive language is processed
Orbiofrontal cortex
Recognized as area of emotional regulation
Parietal lobe part of dorsal visual stream
intraparietal sulcus
Numeric calculation
intraparietal sulcus
Phonolgical procesing
Supramarginal gyrus
Area designated for reading
Angular Gyrus
Primary reception area of body sense
Postcentral Gyrus
Lesion results in acaluclia
Intraparietal Sulcus
Postcentral gyrus
Interior parietal lobule
Area on temporal lobe is primary receptive area for audition
Heschl’s gyrus
comprehension of language
Wernicke’s area
memory
hippocampus
face recognition
fusiform gyrus
T or F:dorsal visual stem is “what” stem
true
Occipital lobe primary reception area for vision
calcarine sulcus
motor programming for speech sounds
insula
critical for sense of taste
insula
sense of self
insula
Distal root fibers of spinal cord are (afferent/efferent) because ______
afferent
Pass into dorsal or posterior part of spinal cord
Carry sensory info to spinal cord
Ventral root fibers of spinal cord are (afferent/efferent) because _____
efferent
Arise from anterior or ventral portion of spinal cord
Carry impulses that cause muscles to move
The information lifeline to and from the periphery of the body
Spinal Cord
Myelin sheath over tracts of the spinal cord
White Matter
Regions of the body served by sensory neurons aka
Dermatomes
Which root fibers are afferent?
Distal root fibers
Cell bodies in spinal cord make up
Gray Matter
Sensory information is carried through the
Dorsal root fibers (afferent)
Motor information is conveyed through the
Ventral root fibers (efferent)
Sensory pathways are known as
afferent
Motor pathways are known as
efferent
Gray matter is made up of
cell bodies
White matter is made up of
Myelinated fibers
Simplest stimulus-response system of nervous system
Spinal Reflex Arc
Pathways through which info reaches higher centers of brain
Tracts
Info entering from the right side of the body ends on the _____ side of the brain
Left
_____ pathways transmit sensory information
Afferent
______ pathways transmit motor commands
Efferent
Because it activates muscles served by the spinal cord it is called the
Corticospinal Tract
Point at which fibers cross from one side to the other is
Pyramidal Decussation
Pyramidal decussation is within the
Medulla
“bulb” refers to the
Brain stem
_____ tract activates cranial nerves
Corticobulbar
Parts of Brainstem
Medulla oblongata
Pons
MIdbrain
Motor nuclei
impulses from cerebrum transmitted by means of corticobulbar tract
XII cranial nerve (hypoglossal) emerges from
Medulla
Immediately above medulla
Pons
Lowest portion of brainstem
Medulla
Superior-most structure of brainstem
Midbrain
Middle cerebellar peduncles arise from
Pons
Pyramidal decussation is within
Medulla
Most of 4th cerebral ventricle is associated w/
Pons
Which nerve innervates muscle of mastication and facial sensation?
V Trigeminal Nerve
Which nerve has both spinal and brainstem components?
XI Accessory
Which branch of trigeminal nerve transmits info about lower teeth?
Mandibular
Which branch of trigeminal nerve provides motor innervation of muscles of mastication?
Mandibular
Which branch of trigeminal nerve provides sensory info concerning maxillary region?
Maxillary
Which nerve provides motor innervation of face?
VII Facial
Which branch or nerve conducts auditory info?
VIII Auditory Branch
Innervates superior pharyngeal constrictor
IX Glossopharyngeal
Innervates muscle most responsible for pitch change in voice
X Vagus Sup. Laryngeal Nerve
Nerve responsible for activation of muscles of tongue
XII Hypoglossal
Innervates muscles of adduction and abduction
X Vagus Rec. Laryngeal Nerve
What role does frontal lobe play?
Cognitive processes
What role does parietal lobe play?
Body sensation
What role does temporal lobe play?
Speech and language
input of auditory information
What are important speech and language areas of temporal lobe?
Heschl’s Gyrus
Wernicke’s Area
Hippocampus
What are important areas of speech and language in occipital lobe?
Damage to INSULAR LOBE could result in Broca’s aphasia and verbal apraxia
Central Fissure aka
Rolandic Fissure or Central Sulcus
between Frontal and Parietal lobes
What are important speech and language areas of Precentral Gyrus of Central Fissure?
Precentral Gyrus aka Motor Strip
SPEECH MUSCLE ACTIVATION (at bottom)
What are important speech and language areas of Premotor Region of Central Fissure?
Broca’s Area
grooves/infolding of cortex
Sulcus
very deep groove
Fissure
Outfolding of cortex
Gyrus
Important site for speech and language because it is the site for input of auditory info
Temporal Lobe
Extremely important for memory processing
Hippocampus
What lobe processes sensory information?
Parietal Lobe
Which area is involved in phonologic analysis?
Supramarginal Gyrus
Which area is involved in reading?
Angular Gyrus
What type of info is processed by occipital lobe?
Visual
