chapter 6: hearing, balance, taste, and smell Flashcards
decibel (dB)
a measure of sound intensity, perceived as loudness
hertz (Hz)
cycles per second, as of an auditory stimuli; measure of frequency
pure tone
one frequency of vibration, represented by a sine wave
amplitude
perceived as loudness, expressed in decibels (dB), also called intensity
frequency
perceived as pitch, measured in hertz (Hz)
fundamental
basic frequency
harmonics
multiples of the fundamental
timbre
sound quality, notes differ in intensities when played by different instruments
transduction
the conversion of one form of energy to another
pinna
the external part of the ear
ear canal
the tube leading from the pinna to the tympanic membrane, also called auditory canal
inner ear
the cochlea and vestibular apparatus
middle ear
the cavity between the tympanic membrane and the cochlea
tympanic membrane
the partition between the external ear and the middle ear, also called eardrum
ossicles
three small bones (incus, malleus, and stapes) that transmit vibration across the middle ear, from the tympanic membrane to the oval window
oval window
the opening from the middle ear to the inner ear
malleus
a middle ear bone that is connected to the tympanic membrane
Latin for “hammer”
incus
a middle ear bone situated between the malleus and the stapes
Latin for “anvil”
stapes
a middle ear bone that is connected to the oval window
Latin for “stirrup”
cochlea
a snail-shaped structure in the inner ear that contains the primary receptor cells for hearing
vestibular canal
one of the three principal canals running along the length of the cochlea
also called scala vestibuli
middle canal
the central of the three spiraling canals inside the cochlea, situated between the vestibular canal and tympanic canal
also called scala media
tympanic canal
one of the three principal canals running along the length of the cochlea
also called scala tympani
round window
a membrane separating the tympanic canal from the middle ear
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
hair cell
one of the receptor cells for hearing in the cochlea
basilar membrane
a membrane in the cochlea that contains the principal structures involved in auditory transduction
stereocilium
a relatively stiff hair that protrudes from a hair cell in the auditory or vestibular system
inner hair cell (IHC)
one of the two types of receptor cells for hearing in the cochlea; positioned close to the central axis of the coiled cochlea
outer hair cell (OHC)
one of the two types of receptor cells for hearing in the cochlea; positioned far from the central axis of the coiled cochlea
vestibulocochlear nerve
cranial nerve VIII, which runs from the cochlea to the brainstem auditory nuclei
tuning curve
a graph of the responses of a single auditory nerve fiber or neuron to sounds that vary in frequency and intensity
cochlear nucleus
either of the two brainstem nuclei – left and right – that receive input from auditory hair cells and send output to the superior olivary nuclei
superior olivary nucleus
either of the two brainstem nuclei – left and right – in the thalamus that receive input from both right and left cochlear nuclei, and provide the first binaural analysis of auditory information
inferior colliculi
paired gray matter structures of the dorsal midbrain that process auditory information
medial geniculate nucleus
either of the two nuclei –left and right – in the thalamus that receive input from the inferior colliculi and send output to the auditory cortex
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
place coding
frequency discrimination in which the pitch of a sound is determined by the location of activated hair cells along the length of the basilar membrane
temporal coding
frequency discrimination in which the pitch of a sound is determined by the rate of firing of auditory neurons
ultrasound
high-frequency sound; in general, above the threshold for human hearing, at about 20,000 Hz
infrasound
very low-frequency sound; in general, below the threshold for human hearing, at about 20 Hz
intensity difference
a perceived difference in loudness between the two ears, which the nervous system can use to localize a sound source
latency difference
a difference between the two ears in the time of arrival of a sound, which the nervous system can use to localize a sound source
spectral filtering
the process by which the hills and valleys of the external ear alter the amplitude of some, but not all, frequencies in a sound
amusia
a disorder characterized by the inability to discern tunes accurately or to sing
conduction deafness
a hearing impairment in which the sound vibrations in air fail to be converted into waves of fluid in the cochlea; associated with defects of the external or middle ear
sensorineural deafness
a hearing impairment most often caused by the permanent damage or destruction of hair cells, or by interruption of the vestibulocochlear nerve that carries auditory information to the brain
tinnitus
a sensation of noises or ringing in the ears not caused by external sound
central deafness
a hearing impairment in which the auditory areas of the brain fail to process and interpret action potentials from sound stimuli in meaningful ways; related to damage in auditory brain areas, such as strokes, tumors, or traumatic injuries
word deafness
a form of central deafness that is characterized by the specific inability to hear words, although other sounds can be detected
cortical deafness
a form of central deafness, caused by damage to both sides of the auditory cortex, that is characterized by difficulty in recognizing all complex sounds, whether verbal or nonverbal
cochlear implant
an electromechanical device that detects sounds and selectively stimulates nerves in different regions of the cochlea via surgically implanted electrodes
vestibular system
the sensory system that detects balance; consists of several small inner-ear structures that adjoin the cochlea
semicircular canal
any 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 in a particular direction
ampulla
an enlarged region of each semicircular canal that contains the receptor cells (hair cells) of the vestibular system
vestibular nucleus
a brainstem nucleus that receives information from the vestibular organs through cranial nerve VIII (the vestibulocochlear nerve)
motion sickness
the experience of nausea brought on by unnatural passive movement, as in car or boat
sensory conflict theory
a theory of motion sickness suggesting that discrepancies between vestibular information and visual information simulate food poisoning and therefore trigger nausea
taste
any of the five basic sensations detected by the tongue: salty, sweet, sour, bitter, and umami
flavor
the sense of taste combined with the sense of smell
papilla
a small bump that projects from the surface of the tongue; contains most of the taste receptor cells
taste bud
a cluster of 50-150 cells that detects tastes; found in the papillae
TR1
a family of taste receptor proteins that, when particular members bind together, form taste receptors for sweet and umami flavors
TR2
a family of bitter taste receptors
umami
one of the five basic tastes – the meaty, savory flavor
gustatory system
the sensory system that detects taste
odor
the sensation of smell
olfaction
the sensory system that detects smell; the act of smelling
anosmia
the inability to detect odors
olfactory epithelium
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
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
glomerulus
a complex arbor of dendrites from a group of olfactory cells
pheromone
a chemical signal that is released outside the body of an animal and affects other members of the same species
vomeronasal system
a specialized sensory system that detects pheromones and transmits information to the brain
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
trace amine-associated receptor (TAAR)
any one of a family of probable pheromone receptors produced by neurons in the main olfactory epithelium