Chapter 9 Flashcards

amplitude
The maximum extent of a single oscillation in a periodic event, such as a sound wave, measured as the distance from peak to trough in a single cycle. In practical terms, amplitude corresponds to the “volume” of a sound. See Box 9.1.
ampulla (pl. ampullae)
An enlarged region of each semicircular canal that contains the receptor cells (hair cells) of the vestibular system. See Figure 9.16.
amusia
A disorder characterized by the inability to discern tunes accurately.
anosmia
The inability to smell.
basilar membrane
A membrane in the cochlea that contains the principal structures involved in auditory transduction. See Figures 9.2, 9.3.
bass
An aspect of pitch corresponding to the subjective experience of low-frequency sounds (especially musical sounds such as bass guitar).
binaural
Pertaining to two ears. Compare monaural.
central deafness
A hearing impairment that is related to lesions in auditory pathways or centers, including sites in the brainstem, thalamus, or cortex. Cortical deafness and word deafness are two examples of central deafness. Compare conduction deafness and sensorineural deafness.
cilium (pl. cilia)
A hairlike extension. The extensions in the hair cells of the cochlea, for example, are cilia. See Figure 9.2.
circumvallate papillae
One of three types of small structures on the tongue, located in the back, that contain taste receptors. See Figure 9.22. Compare foliate papillae and fungiform papillae.
cochlea
A snail-shaped structure in the inner ear that contains the primary receptor cells for hearing. See Figure 9.2.
cochlear implant
An electromechanical device that detects sounds and selectively stimulates nerves in different regions of the cochlea via surgically implanted electrodes.
cochlear nuclei
Brainstem nuclei that receive input from auditory hair cells and send output to the superior olivary complex. See Figure 9.7.
coincidence detector
A device that senses the co-occurrence of two events.
conduction deafness
A hearing impairment that is associated with pathology of the external-ear or middle-ear cavities. Compare central deafness and sensorineural deafness.
cortical deafness
A hearing impairment that is caused by a fault or defect in the cortex.
cupula
A small gelatinous column that forms part of the lateral-line system of aquatic animals and also occurs within the vestibular system of mammals. See Figure 9.18.
deafness
Hearing loss so profound that speech perception is lost.
decibel (dB)
A measure of sound intensity. See Box 9.1.
dendritic knob
A portion of olfactory receptor cells present in the olfactory epithelium. See Figure 9.25.
diffusion tensor imaging (DTI)
A modified form of MRI in which the diffusion of water in a confined space is exploited to produce images of axonal fibertracts.
duplex theory
A theory that we localize sound by combining information about intensity differences and latency differences between the two ears.
ear canal
A tube leading from the pinna to the middle ear.
external ear
The part of the ear that we readily see (the pinna) and the canal that leads to the eardrum. See Figure 9.2.
foliate papillae
One of three types of small structures on the tongue, located along the sides, that contain taste receptors. See Figure 9.22. Compare circumvallate papillae and fungiform papillae.
Fourier analysis
The analysis of a complex pattern into the sum of sine waves. See Box 9.1.
frequency
The number of cycles per second in a sound wave; measured in hertz (Hz). See Box 9.1.
fundamental
The predominant frequency of an auditory tone or a visual scene. Compare harmonic. See Box 9.1.
fungiform papillae
One of three types of small structures on the tongue, located in the front, that contain taste receptors. See Figure 9.22. Compare circumvallate papillae and foliate papillae.
glomerulus (pl. glomeruli)
A complex arbor of dendrites from a group of olfactory cells.
gustatory system
The taste system. See Figure 9.24.
hair cell
One of the receptor cells for hearing in the cochlea. Displacement of hair cells by sound waves generates nerve impulses that travel to the brain. See Figure 9.2.
harmonics
Multiples of a particular frequency called the fundamental. See Box 9.1.
hearing loss
Decreased sensitivity to sound, in varying degrees.
hertz (Hz)
Cycles per second, as of an auditory stimulus. See Box 9.1.
incus (pl. incudes)
Latin for “anvil.” A middle-ear bone situated between the malleus (attached to the tympanic membrane) and the stapes (attached to the cochlea); one of the three ossicles that conduct sound across the middle ear. See Figure 9.2.
inferior colliculi (sing. colliculus)
Paired gray matter structures of the dorsal midbrain that receive auditory information. See Figure 2.12. Compare superior colliculi.
infrasound
Very low-frequency sound; in general, below the threshold of human hearing, at about 20 Hz. Compare ultrasound.
inner ear
The cochlea and vestibular apparatus. See Figure 9.2.
inner hair cell (IHC)
One of the two types of receptor cells for hearing in the cochlea. See Figure 9.2. Compare outer hair cell.
intensity differences
Perceived differences in loudness between the two ears, which can be used to localize a sound source. Compare latency differences.
labeled lines
The concept that each nerve input to the brain reports only a particular type of information.
latency differences
Differences between the two ears in the time of arrival of a sound, which can be employed by the nervous system to localize sound sources. Compare intensity differences.
lateral-line system
A sensory system, found in many kinds of fishes and some amphibians, that informs the animal of water motion in relation to the body surface.
loudness
The subjective experience of the pressure level of a sound. See Box 9.1.
malleus (pl. mallei)
Latin for “hammer.” A middle-ear bone that is connected to the tympanic membrane; one of the three ossicles that conduct sound across the middle ear. See Figure 9.2.
medial geniculate nuclei
Nuclei in the thalamus that receive input from the inferior colliculi and send output to the auditory cortex. See Figure 9.7.
middle ear
The cavity between the tympanic membrane and the cochlea. See Figure 9.2.
minimal discriminable frequency difference
The smallest change in frequency that can be detected reliably between two tones.
mitral cell
A type of cell in the olfactory bulb that conducts smell information from the glomeruli to the rest of the brain. See Figure 9.25.
motion sickness
The experience of nausea brought on by unnatural passive movement, as in a car or boat.
olfactory bulb
An anterior projection of the brain that terminates in the upper nasal passages and, through small openings in the skull, provides receptors for smell. See Figures 2.12, 9.25.
olfactory epithelium (pl. epithelia)
A sheet of cells, including olfactory receptors, that lines the dorsal portion of the nasal cavities and adjacent regions, including the septum that separates the left and right nasal cavities. See Figures 9.25, 9.27, 9.28.
olfactory receptor cell
A type of neuron, found in the olfactory epithelium, which senses airborne odorants via specialized receptor proteins.
organ of Corti
A structure in the inner ear that lies on the basilar membrane of the cochlea and contains the hair cells and terminations of the auditory nerve. See Figure 9.1.
ossicles
Three small bones (incus, malleus, and stapes) that transmit sound across the middle ear, from the tympanic membrane to the oval window. See Figure 9.2.
otoacoustic emission
A sound produced by the cochlea itself, either spontaneously or in response to an environmental noise.
otolith
A small crystal on the gelatinous membrane in the vestibular system. See Figure 9.18.
ototoxic
Toxic to the ears, especially the middle or inner ear.
outer hair cell (OHC)
One of the two types of receptor cells for hearing in the cochlea. See Figure 9.2. Compare inner hair cell.
oval window
The opening from the middle ear to the inner ear. See Figure 9.2.
papilla (pl. papillae)
A small bump that projects from the surface of the tongue. Papillae contain most of the taste receptor cells. See Figure 9.22.
pattern coding
Coding of information in sensory systems based on the temporal pattern of action potentials.
pheromone
A chemical signal that is released outside the body of an animal and affects other members of the same species. See Figure 5.3. Compare allomone.
pinna (pl. pinnae)
The external part of the ear.
pitch
A dimension of auditory experience in which sounds vary from low to high.
place coding
The encoding of sound frequency as a function of the location on the basilar membrane that is most stimulated by the sound..
pure tone
A tone with a single frequency of vibration. See Box 9.1.
round window
A membrane separating the cochlear duct from the middle-ear cavity. See Figure 9.2.
saccule
A small, fluid-filled sac under the utricle in the vestibular system that responds to static positions of the head. See Figure 9.16.
scala media
Also called middle canal. The central of the three spiraling canals inside the cochlea, situated between the scala vestibuli and scala tympani. See Figure 9.2.
scala tympani
Also called tympanic canal. One of three principal canals running along the length of the cochlea. The other two are the scala media and scala vestibuli. See Figure 9.2.
scala vestibuli
Also called vestibular canal. One of three principal canals running along the length of the cochlea. The other two are the scala media and scala tympani. See Figure 9.2.
semicircular canal
One of the three fluid-filled tubes in the inner ear that are part of the vestibular system. Each of the tubes, which are at right angles to each other, detects angular acceleration. See Figure 9.17.
sensorineural deafness
A hearing impairment that originates from cochlear or auditory nerve lesions. Compare central deafness and conduction deafness.
sensory conflict theory
A theory of motion sickness suggesting that discrepancies between vestibular information and visual information simulate food poisoning and therefore trigger nausea.
spectral filtering
Alteration of the amplitude of some, but not all, frequencies in a sound. When performed by the irregular shapes of the external ear, this process is a source of information that assists in the localization of sound sources.
stapedius
A middle-ear muscle that is attached to the stapes. See Figure 9.2.
stapes
Latin for “stirrup.” A middle-ear bone that is connected to the oval window; one of the three ossicles that conduct sounds across the middle ear. See Figure 9.2.
stereocilium (pl. stereocilia)
A relatively stiff hair that protrudes from a hair cell in the auditory or vestibular system. See Figure 9.2.
superior olivary nuclei
Brainstem nuclei that receive input from both right and left cochlear nuclei, and provide the first binaural analysis of auditory information. See Figure 9.7.
T1R
A family of taste receptor proteins that, when particular members heterodimerize, form taste receptors for sweet flavors and umami flavors. Compare T2R.
T2R
A family of bitter taste receptors. Compare T1R.
tastant
A substance that can be tasted.
taste bud
A cluster of 50–150 cells that detects tastes. Taste buds are found in papillae. See Figure 9.22.
taste pore
The small aperture through which tastant molecules are able to access the sensory receptors of the taste bud. See Figure 9.22.
tectorial membrane
A membrane that sits atop the organ of Corti in the cochlear duct. See Figure 9.2.
temporal coding
The encoding of sound frequency in terms of the number of action potentials per second produced by an auditory nerve. Compare place coding.
tensor tympani
The muscle attached to the malleus that modulates mechanical linkage to protect the delicate receptor cells of the inner ear from damaging sounds. See Figure 9.2.
timbre
The characteristic sound quality of a musical instrument, as determined by the relative intensities of its various harmonics.
tinnitus
A sensation of noises or ringing in the ears.
tip link
A fine, threadlike fiber that runs along and connects the tips of stereocilia. See Figure 9.5.
tonotopic organization
A major organizational feature in auditory systems in which neurons are arranged as an orderly map of stimulus frequency, with cells responsive to high frequencies located at a distance from those responsive to low frequencies.
trace amine–associated receptors (TAARs)
A family of probable pheromone receptors produced by neurons in the main olfactory epithelium. TAARs are candidate pheromone receptors, despite being situated outside the vomeronasal organ.
transduction
The conversion of one form of energy to another.
treble
An aspect of pitch corresponding to the subjective experience of high-frequency sounds (especially musical sounds, such as cymbals).
tuning curve
A graph of the responses of a single auditory nerve fiber or neuron to sounds that vary in frequency and intensity.
tympanic membrane
Also called eardrum. The partition between the external ear and the middle ear. See Figure 9.2.
ultrasound
High-frequency sound; in general, above the threshold for human hearing, at about 20,000 Hz. Compare infrasound.
umami
One of the five basic tastes (along with salty, sour, sweet, and bitter), probably mediated by amino acids in foods.
utricle
A small, fluid-filled sac in the vestibular system above the saccule that responds to static positions of the head. See Figure 9.18.
vestibular nuclei
Brainstem nuclei that receive information from the vestibular organs through cranial nerve VIII (the vestibulocochlear nerve).
vestibulo-ocular reflex (VOR)
The brainstem mechanism that maintains gaze on a visual object despite movements of the head.
vestibulocochlear nerve
Cranial nerve VIII, which runs from the cochlea to the brainstem auditory nuclei. See Figures 2.9, 9.2.
vomeronasal organ (VNO)
A collection of specialized receptor cells, near to but separate from the olfactory epithelium, that detect pheromones and send electrical signals to the accessory olfactory bulb in the brain.
vomeronasal system
A specialized chemical detection system that detects pheromones and transmits information to the brain.
word deafness
The specific inability to hear words, although other sounds can be detected.
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