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Questions and Answers
What type of hair cells are primarily responsible for hearing?
What type of hair cells are primarily responsible for hearing?
- Efferent hair cells
- Sensory hair cells
- Inner hair cells (correct)
- Outer hair cells
What happens to outer hair cells when efferent fibers of the auditory nerve are stimulated?
What happens to outer hair cells when efferent fibers of the auditory nerve are stimulated?
- They lengthen and increase sensitivity
- They shorten and affect inner hair cell sensitivity (correct)
- They die and cause complete hearing loss
- They remain unchanged and do not affect hearing
Presbyacusis primarily affects which type of sound frequencies?
Presbyacusis primarily affects which type of sound frequencies?
- High frequencies (correct)
- All frequencies equally
- Medium frequencies
- Low frequencies
How does the basilar membrane’s structure relate to sound frequency perception?
How does the basilar membrane’s structure relate to sound frequency perception?
What reliable cue do ears use to localize low frequency sounds?
What reliable cue do ears use to localize low frequency sounds?
Which structure is NOT part of the auditory pathway?
Which structure is NOT part of the auditory pathway?
Why does destruction of one side of the auditory cortex not result in complete deafness?
Why does destruction of one side of the auditory cortex not result in complete deafness?
Which part of the brain is responsible for processing sound and contains maps for different frequencies?
Which part of the brain is responsible for processing sound and contains maps for different frequencies?
What is the nature of sound waves and their ability to travel?
What is the nature of sound waves and their ability to travel?
Which frequency range represents the most sensitive human hearing perception?
Which frequency range represents the most sensitive human hearing perception?
What determines the loudness of a sound?
What determines the loudness of a sound?
Which component in the ear is responsible for sound amplification?
Which component in the ear is responsible for sound amplification?
What is the consequence of sound reaching 140 dB?
What is the consequence of sound reaching 140 dB?
What measurement unit is used to express loudness?
What measurement unit is used to express loudness?
What role does the Eustachian tube play in the ear?
What role does the Eustachian tube play in the ear?
How is the total amplification of sound achieved in the ear?
How is the total amplification of sound achieved in the ear?
What function does the middle ear reflex primarily serve?
What function does the middle ear reflex primarily serve?
What is the primary difference between perilymph and endolymph?
What is the primary difference between perilymph and endolymph?
Which muscle of the middle ear is innervated by cranial nerve VII?
Which muscle of the middle ear is innervated by cranial nerve VII?
What occurs during the mechanism of hearing due to sound waves?
What occurs during the mechanism of hearing due to sound waves?
What is the latent period of the acoustic reflex, during which it cannot protect the inner ear?
What is the latent period of the acoustic reflex, during which it cannot protect the inner ear?
Where is the organ of Corti located?
Where is the organ of Corti located?
What is the result of potassium influx into hair cells?
What is the result of potassium influx into hair cells?
What is the role of the tensor tympani muscle in the middle ear?
What is the role of the tensor tympani muscle in the middle ear?
Which location houses the hair cells responsible for detecting head movement in the semicircular canals?
Which location houses the hair cells responsible for detecting head movement in the semicircular canals?
What happens to the capula during head rotation?
What happens to the capula during head rotation?
What is the effect of the capula bending away from the kinocilium?
What is the effect of the capula bending away from the kinocilium?
What occurs when endolymph moves during caloric stimulation with cold water?
What occurs when endolymph moves during caloric stimulation with cold water?
What phenomenon describes the sensation of rotation without actual movement?
What phenomenon describes the sensation of rotation without actual movement?
How does the frequency of action potentials change during head rotation?
How does the frequency of action potentials change during head rotation?
What latent effect occurs if a person stops rotating suddenly?
What latent effect occurs if a person stops rotating suddenly?
How do the semicircular canals function in pairs?
How do the semicircular canals function in pairs?
What is the primary function of the vestibular system?
What is the primary function of the vestibular system?
Which chamber is responsible for sensing linear vertical acceleration?
Which chamber is responsible for sensing linear vertical acceleration?
What role does the kinocilium play in the sensory process of the macula?
What role does the kinocilium play in the sensory process of the macula?
What is the composition of the space between the osseous and membranous labyrinth in the vestibular system?
What is the composition of the space between the osseous and membranous labyrinth in the vestibular system?
How does the bending of cilia affect hair cell excitation in the vestibular system?
How does the bending of cilia affect hair cell excitation in the vestibular system?
What is the primary responsibility of Wernicke's area in the secondary auditory area?
What is the primary responsibility of Wernicke's area in the secondary auditory area?
Which part of the vestibular system is responsible for detecting angular acceleration?
Which part of the vestibular system is responsible for detecting angular acceleration?
What does the macula contain that is essential for its sensory function?
What does the macula contain that is essential for its sensory function?
Which of the following describes the function of the vestibulo-ocular reflex (VOR)?
Which of the following describes the function of the vestibulo-ocular reflex (VOR)?
What is the primary role of the vestibular system?
What is the primary role of the vestibular system?
During physiologic nystagmus, what occurs after the eyes reach an extreme position during prolonged head rotation?
During physiologic nystagmus, what occurs after the eyes reach an extreme position during prolonged head rotation?
What happens when the right horizontal semicircular canal is stimulated while the head rotates to the right?
What happens when the right horizontal semicircular canal is stimulated while the head rotates to the right?
Which cranial nerves are involved in the pathways from the vestibular nuclei?
Which cranial nerves are involved in the pathways from the vestibular nuclei?
What type of movement is characterized as slow and occurs opposite to the direction of head rotation during nystagmus?
What type of movement is characterized as slow and occurs opposite to the direction of head rotation during nystagmus?
Which structure terminates the vestibular nerve?
Which structure terminates the vestibular nerve?
In the context of the vestibular system, what role do the extra-ocular muscles serve during head rotation?
In the context of the vestibular system, what role do the extra-ocular muscles serve during head rotation?
Flashcards
Pinna
Pinna
The part of the ear that collects and directs sound waves towards the ear canal.
External Auditory Meatus
External Auditory Meatus
The ear canal, which is the tube that transmits sound waves from the pinna to the eardrum.
Tympanic Membrane
Tympanic Membrane
A thin membrane in the middle ear that vibrates when sound waves hit it.
Ossicles
Ossicles
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Eustachian Tube
Eustachian Tube
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Cochlea
Cochlea
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Frequency
Frequency
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Amplitude
Amplitude
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Middle ear reflex
Middle ear reflex
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Tensor tympani
Tensor tympani
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Stapedius
Stapedius
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Attenuation reflex
Attenuation reflex
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Perilymph
Perilymph
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Endolymph
Endolymph
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Organ of Corti
Organ of Corti
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Tectorial membrane
Tectorial membrane
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Role of outer hair cells
Role of outer hair cells
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Basilar membrane and frequency discrimination
Basilar membrane and frequency discrimination
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What is presbyacusis?
What is presbyacusis?
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Describe the auditory pathway
Describe the auditory pathway
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Why does damage to one side of the auditory system not cause complete deafness?
Why does damage to one side of the auditory system not cause complete deafness?
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What is the primary auditory cortex?
What is the primary auditory cortex?
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How does sound localization work?
How does sound localization work?
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Role of the superior olivary nucleus
Role of the superior olivary nucleus
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Auditory Association Cortex
Auditory Association Cortex
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Vestibular System
Vestibular System
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Utricle and Saccule
Utricle and Saccule
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Macula
Macula
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Kinocilium
Kinocilium
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Stereocilia
Stereocilia
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What is the function of the vestibular system?
What is the function of the vestibular system?
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What is another key function of the vestibular system?
What is another key function of the vestibular system?
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What is the third important function of the vestibular system?
What is the third important function of the vestibular system?
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What is the main function of the vestibulo-ocular reflex (VOR)?
What is the main function of the vestibulo-ocular reflex (VOR)?
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What is physiologic nystagmus?
What is physiologic nystagmus?
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What is the quick movement phase of physiologic nystagmus?
What is the quick movement phase of physiologic nystagmus?
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What happens to the eye muscles during rightward head rotation?
What happens to the eye muscles during rightward head rotation?
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Where does the vestibular nerve terminate?
Where does the vestibular nerve terminate?
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Semicircular canals
Semicircular canals
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Hair cells in the ampulla
Hair cells in the ampulla
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Vertigo
Vertigo
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Caloric stimulation
Caloric stimulation
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Nystagmus
Nystagmus
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Endolymph movement in semicircular canals
Endolymph movement in semicircular canals
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Paired function of semicircular canals
Paired function of semicircular canals
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Study Notes
The Ear
- The ear is a mechanoreceptive organ containing mechanoreceptors.
- It functions in hearing (responding to sound waves) and equilibrium (balance).
- Sound waves comprise vibrations of air molecules, characterized by peaks (maximum compression) and troughs (maximum rarefaction).
- Sound waves can travel through liquids, solids, and gases, but not vacuum.
Qualities of Sound
- Pitch: Related to frequency (number of sound waves passing a fixed point per second, measured in Hertz (Hz)).
- Human hearing range is 20-20,000 Hz, most sensitive to 1000-4000 Hz (human speech).
- Loudness (intensity): Related to the amplitude of sound waves (difference between maximum and minimum pressure).
- Measured in decibels (dB). Zero decibels represents the standard intensity.
- An x-fold increase in sound intensity corresponds to an increase in dB of 10*log(x).
- Normal conversation is roughly 60 dB.
- Discomfort and damage to hearing receptors occur around 140 dB.
- Pain occurs at around 160 dB.
Direction of Sound
- Determined by the spatial relationship between the sound source and the listener.
Physiologic Anatomy
- Outer Ear: Pinna (collects and directs sound), external auditory meatus.
- Middle Ear: Tympanic membrane (eardrum); ossicles (malleus, incus, stapes) and associated muscles (stapedius and tensor tympani).
- Inner Ear: Cochlea (sensory organ of hearing), Eustachian tube.
Amplification of Sound
- The ossicles act as a lever system, amplifying sound energy transfer from the air to the denser liquid medium in the inner ear.
- The surface area of the tympanic membrane is significantly larger than that of the oval window, providing further amplification.
Attenuation (Acoustic) Reflex
- Loud sounds trigger a reflex contraction of muscles in the middle ear.
- This reflex decreases transmission of low-frequency sounds to protect the inner ear from damage by sudden loud sounds.
- Helps to mask low-frequency background noise.
Cochlea
- The cochlea is a spiraled tube divided into three sections by membranes.
- The scala vestibuli and scala tympani contain perilymph.
- The scala media contains endolymph.
- Inside the scala media is the organ of Corti, containing hair cells with stereocilia.
- Perilymph has similar composition to extracellular fluid (ECF), with high sodium and low potassium.
- Endolymph has high potassium and low sodium levels.
Hair Cells
- Inner hair cells are the primary sensory cells for hearing.
- Outer hair cells are involved in amplifying the response of inner hair cells.
- Damage to hair cells can result in hearing loss.
Pitch Discrimination
- Pitch is determined by which part of the basilar membrane vibrates.
- The base of the membrane vibrates to high-frequency sounds and the apex to low-frequency sounds.
- Basilar fibers at the base are short and stiff, while those at the apex are long and flexible.
Auditory Pathway
- Auditory information travels from the cochlea through various nuclei (e.g., superior olivary nucleus, lateral lemniscus, inferior colliculus, medial geniculate body) before reaching the auditory cortex.
Cortical Auditory Areas
- Primary auditory areas are located in the superior temporal lobe.
- These areas receive information from the medial geniculate body.
- Secondary auditory areas are located near the primary areas, integrating sound information with other sensory inputs.
Vestibular System
- Located in the inner ear, it consists of utricle, saccule, and semicircular canals.
- Responsible for balance (equilibrium) and spatial orientation, responding to head position and movement.
- The utricle and saccule detect linear acceleration and head position.
- Semicircular canals detect angular acceleration (rotation).
- The macula within utricle and saccule contains hair cells embedded in a gelatinous matrix containing calcium carbonate crystals (otoconia), which shift position with changes in head orientation.
- Displacement of otoconia or endolymph bending cilia cause hair cells to become stimulated or inhibited, leading to afferent signal generation in peripheral vestibular afferents.
Caloric Stimulation of the Vestibular Apparatus
- Irrigation of the ear with hot or cold water causes endolymph movement.
- This movement stimulates the horizontal semicircular canals (in opposite directions based on water temperature).
- This stimulation can cause nystagmus (involuntary eye movements), suggesting the direction of head movement.
Vestibulo-ocular Reflex (VOR)
- Reflex that stabilizes retinal images during head rotation.
- Eyes move in the opposite direction of head rotation to maintain visual focus
Additional Notes
- Damage to the vestibular system can cause vertigo and balance disorders.
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Description
Test your knowledge on the auditory system through this quiz, which covers the functions of hair cells, sound frequency perception, and the brain's role in processing sound. Questions will explore topics such as presbyacusis, sound wave properties, and the structures involved in hearing.
