Term
| What is the adequate stimulus for the auditory receptors? |
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Definition
| sound waves with frequencies between 20 & about 20,000 Hz |
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Term
| The _____ of sound waves determines the pitch, whereas the _____ of the waves determines the intensity |
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Definition
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Term
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Definition
| a chain of 3 tiny bones to which the tympanic membrane transmits sound waves it receives through the air |
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Term
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Definition
| the sensory cells of the cochlea; low-threshold mechanoreceptors sensitive to the bending of stereocilia on their surface |
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Term
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Definition
| where the cochlea conducts signals to in the brain stem via the 8th cranial nerve (vestibulocochlear nerve) |
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Term
| From the cochlear nuclei, what kind of pathways carry signals to the inferior colliculus? |
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Definition
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Term
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Definition
| part of the thalamus where neurons in the inferior colliculus send their axons |
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Term
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Definition
| situated on the upper face of the temporal lobe; where thalamocortical axons reach |
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Term
| What is crucial for our ability to localize sounds? |
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Definition
| nuclei in the brain stem receiving signals from both ears with a time difference |
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Term
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Definition
| an outer bony part surrounding an irregular canal in the temporal bone & an inner membranous part following & partly filling the canal |
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Term
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Definition
| the fluid that fills the membranous canal of the labyrinth |
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Term
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Definition
| the fluid that fills the space between the membranous & the bony parts of the labyrinth |
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Term
| The cilia of the sensory cells of the labyrinth, surrounded by the endolymph, are embedded in an unusual ECF with _____ as the dominating cation |
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Definition
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Term
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Definition
| the potential of about 90 mV between the endolymph & the perilymph created by the high K+ concentration |
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Term
| membranous part of the cochlea (the cochlear duct) |
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Definition
| forms a thin-walled tube with a triangular shape, surrounded by the bony part of the cochlea |
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Term
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Definition
| forms the lowermost wall of the cochlear duct; suspended between the two facing sides of the bony canal |
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Term
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Definition
| a bony prominence to which the basilar membrane is attached at the inner side of the turns of the cochlear duct; follows the cochlea in its spiraling course |
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Term
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Definition
| the sensory epithelium of the cochlea that rests on the basilar membrane |
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Term
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Definition
| a thin membrane that forms the upper wall of the cochlear duct |
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Term
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Definition
| a specialized, stratified epithelium that forms the third, lateral (outer) wall of the cochlear duct which lies on the bony wall of the canal |
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Term
| Are there capillaries among the epithelial cells of the cochlea? |
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Definition
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Term
| The canal situated below the basilar membrane is the _____; the one above the vestibular membrane is the _____ |
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Definition
| scala tympani; scala vestibuli |
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Term
| What is the difference between the oval window & the round window? |
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Definition
oval: situated at the end of the scala vestibuli
round: at the end of the scala tympani |
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Term
| 2 places where the conduction of sound waves from the air to the receptor cells in the cochlea occurs through |
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Definition
1. external ear
2. tympanic cavity (middle ear) |
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Term
Sound waves hit the _____ located at the bottom of the external meatus
*AKA eardrum |
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Definition
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Term
| The eardrum consists of a thin, tense connective tissue membrane covered by a thin layer of epithelium on both sides; it is richly supplied with _____, like the tight skin of the inner part of the external meatus |
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Definition
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Term
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Definition
| a set of 3 structures that form a chain through the middle ear & connect the eardrum with the oval window |
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Term
| The _____ has a shaft that is attached to the inner side of the eardrum |
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Definition
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Term
| The head of the malleus connects to the _____ by a joint, & that part is further connected to the _____ by a joint |
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Definition
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Term
| Normally, even the slightest movement of the eardrum is sufficient to cause stimulation of the receptors in the cochlea: sound waves with an amplitude of only _____ nm suffice to produce the weakest perceptible sound with the frequency to which the ear is most sensitive |
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Definition
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Term
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Definition
| connects the middle ear cavity with the pharynx |
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Term
| 2 things that form the 2 populations of receptor cells along the basilar membrane |
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Definition
1. outer hair cells
2. inner hair cells |
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Term
| What kind of cells surround the hair cells? |
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Definition
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Term
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Definition
| two rows of especially large supporting cells that separate the inner & outer hair cells & form the tunnel of Corti |
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Term
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Definition
| a thick plate that lies above the hair cells & is indirectly attached to the bony wall of the cochlea |
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Term
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Definition
| the midportion of the cochlea close to which the bony spiral lamina is located which houses the cell bodies of the sensory neurons |
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Term
| _____ also contact the hair cells, enabling the CNS to control the sensitivity of the auditory receptors |
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Definition
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Term
| What is caused by movement of the basilar membrane & produces receptor potentials in both inner & outer hair cells |
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Definition
| deflection of the stereocilia |
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Term
| Bending of the stereocilia toward the longest cilium (hyperpolarizes or depolarizes?) it |
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Definition
| depolarizes it (the opposite movement hyperpolarizes it) |
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Term
| What does the depolarization of the stereocilia produce? |
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Definition
| a graded receptor potential |
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Term
| Depolarization of the hair cell is most likely caused by opening of _____ near the tip of the stereocilia |
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Definition
| mechanosensitive ion channels |
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Term
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Definition
| a thin protein thread by which the stereocilia are interconnected near their tips |
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Term
| Depolarization leads to the release of _____ from the basal part of the inner hair cells |
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Definition
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Term
| Are there mechanisms intrinsic to the cochlea that can amplify the vibrations of the basilar membrane almost 100 times? |
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Definition
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Term
| How do outer hair cells work as the motors of amplification? |
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Definition
| they can rapidly transmit mechanical energy to a very narrow strip of the basilar membrane |
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Term
What kind of activity is initiated by the receptor potential?
(hint: it changes the form of the cell) |
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Definition
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Term
| The efferent fibers ending on the outer hair cells release _____ that hyperpolarizes the cells by binding to muscarine receptors |
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Definition
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Term
| The ordered arrangement of neurons & nerve fibers signaling different pitches of sound is called _____ localization |
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Definition
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Term
| Are tones with the highest or lowest pitch registered by the hair cells closes to the oval window? |
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Definition
| highest pitch (lowest frequencies are registered at the top of the cochlea due to the tonotopic localization) |
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Term
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Definition
| each position along the basilar membrane corresponds to a certain frequency (Helmholtz's theory) |
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Term
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Definition
| the part of the 8th cranial nerve conducting signals from the cochlea |
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Term
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Definition
| where most of the fibers of the cochlear nerve (most of which are afferent) have their cell bodies; located in the bony spiral lamina |
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Term
| 2 cochlear nuclei that are located laterally on the medulla into which the cochlear nerve enters |
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Definition
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Term
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Definition
| where the efferent fibers of the cochlear nerve arise; located in the rostral part of the medulla |
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Term
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Definition
| the pathway formed by the ascending fibers from the cochlear nuclei |
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Term
| inferior collicular brachium |
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Definition
| an oblong elevation at the dorsal side of the mesencephalon formed by the efferent fibers of the cochlear nuclei |
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Term
| Neurons in the inferior colliculus respond specifically to sound from a certain direction, & the inferior colliculus probably contains a map of our _____ |
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Definition
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Term
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Definition
| formed from efferent fibers in the cochlear nerve that end in contact primarily with the outer hair cells of the cochlea & come from the superior olivary complex |
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Term
| 2 transmitters used by the many inhibitory interneurons in the nuclei of the auditory pathways |
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Definition
1. GABA (gamma-aminobutyric acid)
2. glycine |
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Term
| Why is selective suppression of auditory information necessary? |
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Definition
| we need to be able to select the relevant sounds among numerous irrelevant ones |
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Term
| Are auditory neurons inhibited during vocalization? |
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Definition
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Term
| The reticular formation receives collaterals from the ascending auditory pathways, & such connections mediate _____ |
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Definition
| the sudden muscle activity provoked by a strong, unexpected sound (a startle response) |
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Term
| Paresis of what nerve often is accompanies by hypersensitivity to sounds (hyperacusis)? |
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Definition
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Term
| Are there reflex arcs that mediate autonomic movements of the head & eyes & even the body in the direction of an unexpected sound? |
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Definition
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Term
| 2 places where the centers for movements of the head & eyes in response to an unexpected sound are located |
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Definition
1. inferior colliculus
2. superior colliculus |
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Term
| What takes place in the superior colliculus? |
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Definition
| integration of auditory, visual, & somatosensory information so that the final motor response is appropriate for the organism as a whole |
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Term
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Definition
| a region on the upper face of the temporal lobe where AI is situated |
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Term
| Do all neurons in AI depict simple, physical features of sounds? |
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Definition
| no! (some have surprisingly complex properties) |
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Term
| Can the response of many neurons depend on the context of a stimulus? |
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Definition
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Term
| Does the object with which a sound is associated modulate the activity of many AI neurons? |
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Definition
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Term
| Where does the auditory belt receive its main afferents from? |
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Definition
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Term
| Do many neurons appear to respond best to species-specific sounds? |
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Definition
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Term
| Do different subregions of the auditory belt deal with the "what" (the frequency composition of the sound) & "where" (the localization in the space of the sound source)? |
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Definition
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Term
| 2 divisions in the frontal lobe for the "what" & the "where" of sounds |
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Definition
"what" = ventral
"where" = dorsal |
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