NRSC 277 Exam 3
20 Hz- 20,000 Hz 20,000 Hz
Humans are sensitive to sounds with vibrations between what and what. Then, most mammals are sensitive to frequencies higher than what?
stapes
movement of which part of the ossicle causes at traveling waves of deformation along the basilar membrane > the traveling wave reaches peak amplitude at a location that depends on the frequency of the stimulus
hair cell microvilli
multiple stereocilia + 1 single kinocilium (true cilium)
widens at apex, stiffness decreases from base to apex, and endolymph movement bends basilar membrane near base, wave moves towards apex
breakdown the response of basilar membrane to sound
nystagmus
normal physiological __________________ is a fast eye movement following the slow movements of the vestibular ocular reflex. the fast movement is in the same direction of head turning and its function is to return the eyes to the center of the orbit. the whole purpose of this is to keep images from moving on the retina
otoconia
each macula has gelatinous substance containing calcium carbonate crystal called what
utricle
each semicircular duct communicates at both ends with the ________________.
ampulla
each semicircular duct has this dilation at one end of each duct. this also contains a crista, containing sensory hair cells and supporting cells. the ampullary crest is the sensory organ.
rotary and caloric
clinically _______________ and ________________ nystagmus tests are used to diagnose vestibular disorders
utricle
a large chamber at the confluence of the three semicircular canals
motor unit
a motor neuron and all the muscle fibers/cells it innervates
vertigo
a sensation of turning or rotation in space without actual rotation
tonotopic organization
columnar organization of cells with similar binaural interaction
right right left
fill in da blank: When a person is sitting on a spinning chair rotating to the right very quickly and suddenly stops - In the beginning of the rotation> _________________- beating rotating nystagmus. Throughout the rotation > ________________- beating nystagmus When the rotation stopped > brief period of ____________- beating rotation nystagmus.
- sound vibrations go to tympanic membrane - then to ossicles - then to oval window
gimme a breakdown of how sound travels through the middle ear
hypercusia
an increased activity in the tensor tympani muscle that is part of the "startle response" to some sounds
towards= depolorization away= hyperpolarization
hair cells activated by the deflection or shearing of the stereocilia. shearing IN the direction of the kinocolium= what , and shearing AWAY from kinocilium = what.
primary auditory cortex
axons leaving medial geniculate nucleus project to this, it's similar to corresponding visual cortex areas
tonotopic maps on the basilar membrane
how can you determine stimulus frequency in the cochlea
through an earphone, through the forehead with a vibrator
how do you test air conduction and bone conduction?
bony labrynth
part of the inner ear that is a system of bony tubes
tallest stereocilia
deflecting the microvilli toward the ______________________ __________________________ stretches the tiplinks > increases the probability of the mechanically gated cation channel opening > inward K+ current > hair depolarization > voltage dependent calcium channels opening > neurotransmitter release onto eighth nerve endings
location
depends on a comparison of sounds reaching the 2 ears and the CNS
nope, just some difficulty with background noise
if you have a lesion in your auditory cortex are you deaf???
optokinetic nystagmus
induced by moving visual stimuli (like when a person sits in a fast moving train and seeing the telephone poles outside the window)
outer hair cells
inner or outer: 3~5 cells wide, directly above the basilar membrane, total abuot 15,000 cells/per ear
inner hair cells
inner or outer: a single row of hair cells near the edge of the osseous spiral lamina, total about 3500 cells per ear
outer hair cells
inner or outer: the stereocilia are inserted into the tectorial membrane, so the vibration of the basilar membrane causes oscillations of the hairs and the membrane potential of the hair cells
inner hair cells
inner or outer: these hair cells are not attached to the tectorial membrane, and they are stimulated directly by movement of endolymph within the cochlear duct
caloric nystagmus
instilling cool or warm water into a subject's ear causes endolymphatic convection currents and that will induce nystagmus.
peripheral mechanism
interaural time delay and interaural intensity difference
sound waves tympanic membrane ossicles oval window cochlear fluid sensory neuron response
list out the auditory pathway stages (hint: there's six)
perilymph
pressure at the oval window pushes what fluid into the scala vestibuli, round window membrane bulges out
intermediate fibers
properties that are in between red and white fibers
frequency
rate of air pressure change is its ______________________. number of cycles per second expressed in units called hertz. it is the distance between successive compressed patches of air.
angular acceleration
semicircular ducts detect __________________________ _____________________ of the head that accompanies rotation of the head
interaural intensity difference
sound at high frequency from one side or ear
vestibular system or cerebellum
spontaneous nystagmus is a symptom of damage to the what or the what.
intensity, frequency, and location
the auditory system encodes information of a sound based on what three things of the stimulus
cupula
the hair cells are embedded in a gelatinous mass called the _______________. this covers the crista and extends across the ampulla
vestibular axons
the push pull arrangement of these helps sense all possible head rotation angles, each paired with another on opposite side of the head
perilymph endolymph
the scala vestibule and scala tympani contain: ___________ the scala media (cochlear duct) contains: ________________
macula
the supporting cells of utricles and saccules that are located on the walls along with hair cells as patches. this is a receptor organ.
tunnel of corti
the two groups of hair cells in the organ of corti are the inner and outer hair cells. what are they separated by
horizontal vertical
the utricular macula is lying at the bottom of the utricle and what orientation is it. the saccular macula is on the medial wall of the saccule, and is roughly what orientation.
air conduction and bone conduction
there are two ways of the sound conduction, what are they
hair cells
these are specialized microvilli in one end and the other end form synapses onto cranial nerve VIII
hair cells
these things are bound by tight junctions and have synaptic vesicles. they are activated by the deflection or shearing of the stereocilia
utricle and saccule
these two otolith organs located inside the vestibule detect changes in head angle and linear acceleration
vestibular labyrinth
this consists of 2 otolith organs (which control garvity and tilt) and 3 semicircular canals (controls head rotation) uses hair cells, like the auditory system to detect changes
intensity
this is coded by the action potential firing rate of the VIII nerve fibers and the numbers of the nerve fibers
frequency
this is indicated by the particular part of the organ of corti that is most active
endolymph
this is produced continuously by specialized cells in several locations in the membranous labrynth. it flows from the semicircular ducts into the utricle, and from the cochlear duct into the saccule.
the attenuation reflux
this is the response where the onset of loud sound causes tensor tympani and stapedius muscle contraction
external ear
this part of the ear includes the pinna and associated structures. its function is auditory in nature.
middle ear
this part of the ear includes the tympanic membrane, ossicular chain, round window and oval window, and eustachian tube connecting to the nasopharynx. its function is auditory in nature.
inner ear
this part of the ear includes vestibular and auditory functions. (cochlea, etc)
superior olivary nucleus
this receives inputs from both cochlear nuclei, and this is where the time differences of the neuronal signals reach to
horizontal vestibulo-ocular reflex
this reflex consists of slow movement of the eyes opposite to the direction of head rotation. it involves all three sets of semicircular canals
vestibulo-ocular reflex
this senses rotations of the head, commands compensatory movement of eyes in opposite direction.
vestibular system
this system controls our sense of balance, by the vestibular division - head and body location, head and body movements
auditory system
this system controls our sense of hearing and audition by the cochlear division. detects sound and perceives and interprets nuances
motor neurons in the spinal cord ventral horn
this type of lower motor neuron has axons that travel in ventral roots of the spinal cord and innervate their target muscles
autonomic ganglion neurons
this type of lower motor neurons innervate the smooth muscles, organs, and glands
white fibers
this type of skeletal muscle fiber is larger, contains relatively few mitochondria; use anaerobic metabolism; contract in brief and powerful twitches; contract and fatigue rapidly (think sprinters)
interaural time delay
time taken for sound to reach from ear to ear
pathologies of conductive system
what are these things: blockage of external ear canal, perforation or rupture of tympanic membrane, otitis media (middle ear infection), otosclerosis
alcohol, age, or trauma
what are three conditions that make cupula sensitive to gravity cause nystagmus and illusions of movement
alcohol consumption
what causes the density of endolymph altered by being less dense, so a little rotation of the head will cause endolymph rotate much easier and longer, which further excites or suppresses the hair cells
motor proteins
what changes the length of outer hair cells
Meniere's disease
what disease is the defective circulation of absorption of endolymph transient attacks of vertigo, nausea, hearing loss, ringing in the ears
40-70 stereocilia and one larger kinocilium
what does each hair cell consist of
oval window
what has greater pressure and moves fluid, the oval window or the tympanic membrane
prestin
what is required for outer hair cell movements
audible variations in air pressure
what is sound
cochlea
what is the hearing apparatus of the inner ear
balance, equilibrium, posture, head, body, eye movement
what is the importance of the vestibular system
the organ of corti
what is the sensory receptor organ of the cochlea. it lies on the basilar membrane and is composed of hair cells and support structures.
Innervation
what of hair cells is composed of one spiral ganglion fiber/axon, one inner hair cell, numerous outer hair cells
semicircular canals (three)
what part of the vestibular system senses head rotation in different planes
utricle and saccule
what parts of the vestibular system detect static balance (tilt) and liner acceleration (gravity)
peripheral auditory system
what system has the job of converting airborne mechanical waves into electrochemical activity in the nerve cells
striated
what type of muscle includes cardiac and skeletal muscles
smooth
what type of muscle makes up the digestive tract, arteries and related structures
sensorineural hearing loss
when someone has hearing loss in both air conduction and bone conduction
conductive hearing loss
when someone hears normally by bone conduction but not by air conduction
endolymphatic fluid
when the head undergoes rotational acceleration in the plane of the canal, what pushes against the cupula, causing a shearing action that either excites or suppresses the hair cells.
perception/anticipation
the lowered reflex threshold for tensor tympani muscle contraction is activated by the _________________________/_________________ of loud sound, and is called tonic tensor tympani syndrome. Tensor tympani contracts bilaterally in response to something touching the face and before speech production.
perilymph
the part of the inner ear that is fluid inside the bony labrynth. it is similar to the cerebrospinal fluid (high sodium and low potassium)
endolymph
the part of the inner ear that is fluid within the membranous labrynth. it is similar to the intracellular fluid (high potassium)
membranous labrynth
the part of the inner ear that is the membranous tube suspended within the bony labrynth
vestibulo-ocular reflex
the pathway involved in the vestibular nystagmus is called what
air
air or bone: hearing by this type of conduction requires normal function of the outer, middle and inner ears
bone
air or bone: this type of conduction involves direct transmission of vibrations from the skull to the fluids of the inner ear, by passing the outer and middle ears.
motor neuron pool
all the motor neurons that innervate a single muscle
red fibers
a type of skeletal muscle fiber that is thin, contains abundant mitochondria; contract weakly and slowly. they are able to sustain contractions for long periods of time (think marathon runners)
otoacoustic emissions
a vibrating tympanic membrane would behave like a tiny loud speaker producing sound. after a brief sound stimulus, a sensitive microphone in the external auditory canal can detect faint sounds emitted by the ear itself. testing this is very useful for testing the hearing of infants.
tympanic membrane
The auricle (pinna) and external auditory canal (meatus) conduct sound to the ________________________ ____________________. This plays a role in locating sound sources, and selectively amplifies some frequencies of sound.
endolymph, perilymph
The stereocilia and the apical surfaces of hair cells are exposed to _________________, and the synaptic surface of the hair cells and the cranial nerve VIII terminals are bathed in ____________________
sound localization
This involves BOTH peripheral mechanism and central (CNS) mechanism. Depends on comparing the time of arrive to both ears and comparing the intensity of a sound at both ears.
