Chapter 6 (Hearing, Balance, Taste, and Smell) Flashcards
transduction
The conversion of one form of energy to another.
pinna
The external part of the ear.
ear canal
Also called auditory canal. The tube leading from the pinna to the tympanic membrane.
inner ear
The cochlea and vestibular apparatus.
middle ear
The cavity between the tympanic membrane and the cochlea.
tympanic membrane
Also called eardrum. The partition between the external ear and the middle ear.
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
Latin for “hammer.” A middle-ear bone that is connected to the tympanic membrane.
incus
Latin for “anvil.” A middle-ear bone that is connected to the malleus and the stapes.
stapes
Latin for “stirrup.” A middle-ear bone that is connected to the oval window.
cochlea
A snail-shaped structure in the inner ear that contains the primary receptor cells for hearing.
vestibular canal
Also called “scala vestibuli.” One of three principal canals running along the length of the cochlea.
middle canal
Also called “scala media.” The central of the three spiraling canals inside the cochlea, situated between the vestibular canal and the tympanic canal.
tympanic canal
Also called “scala tympani.” One of the three principal canals running along the length of the cochlea.
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. Compared to outer hair cells, IHCs are positioned closer 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. Compared to inner hair cells, OHCs are positioned farther 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 two brainstem nuclei–left and right–that receive input from the auditory hair cells and send output to the superior olivary nuclei.
superior olivary nucleus
Either of two brainstem nuclei–left and right–that receive input from both right and left cochlear nuclei, and provide the birst binaural analysis of auditory information.
inferior colliculi
Paired gray matter structures of the dorsal midbrain that process auditory information.
medial geniculate nucleus
Either of 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 ar 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 20,000Hz.
infrasound
Very low frequency sound; in genral, below the threshold for human hearing, at about 20Hz.
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. It is associated with defects of the external ear 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. It is related to damage in auditory brain areas, such as by 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. It 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 tubs, 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.
motion sickness
The experience of nausea brought on by unnatural passive movement, as in a 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: sweet, salty, 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. Papillae contain most of the taste receptor cells.
taste bud
A cluster of 50-150 cells that detects tastes. Taste buds are found in papillae.
Salty & Sour
Similar to ionotropic receptors
Sweet
More like metabotropic receptors (second messengers)
Umami
One of the five basic tastes–the meaty, savory flavor. (Similar to metabotropic glutamate receptor)
T1R
A family of taste receptor proteins that, when particular members bind together, form taste receptors for sweet flavors and umami flavors.
T2R
A family of bitter taste receptors.
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 (VNO)
A specialized sensory system that detects pheromones and transmits information to the brain.
trace amine-associated receptor (TAAR)
Any one of a family of probable pheromone receptors produced by neurons in the main olfactory epithelium.
