Term
| What are the three parts of the ear? |
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Definition
External- Auricle to tympanic membrane
Middle- Tympanic membrane to round and oval windows
Inner- Everything past the round and oval windows |
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Term
| Which parts of the ear are involved only with hearing? |
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Definition
| The external and middle ear |
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Term
| Which parts of the ear are involved with hearing and balance? |
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Definition
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Term
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Definition
| The auricle is the fleshy part of the external ear on the outside of the head. (External Ear) |
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Term
| What is the external auditory canal? |
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Definition
| The external auditory canal is a passageway that leads to the eardrum. (External Ear) |
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Term
| What are ceruminous glands? |
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Definition
| Glands that line the auditory canal. They produced a modified sebum called cerumen which is commonly called earwax |
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Term
| What is cerumen and what is it's function? |
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Definition
| Cerumen is a modified sebum commonly called earwax. Cerumen and hairs help prevent foreign objects from reaching the delicate tympanic membrane. |
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Term
| What is the typmanic membrane? |
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Definition
| Commonly refered to as the eardrum, it is a thin membrane that separates the external ear from the middle ear. It consists of a this layer of connective tissue sandwiched between two epithelial layers. Sound waves reaching the tympanic membrane cause it to vibrate. |
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Term
| What are the oval and round windows? |
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Definition
| Covered openings on the medial side of the middle ear connecting the inner ear with the inner ear. |
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Term
| Name the auditory ossicles. |
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Definition
| Malleus, incus and stapes |
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Term
| What is the function of the auditory ossicles? Name the role of each one. |
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Definition
The auditory ossicles are bones which transmit vibrations from the tympanic membrane to the oval window.
Malleus- attached to the surface of the tympanic membrane
incus- connects the malleus to the stapes
stapes- seated in the oval window, surrounded by a flexible ligament. |
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Term
| When are vibrations in the middle ear amplified, and by how much? |
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Definition
| As vibrations are transmitted from the malleus to the stapes, the are amplified about 20-fold. |
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Term
| What is the role of the two small muscles attached to the malleus and stapes? |
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Definition
| They dampen vibrations to help protect the delicate inner ear structures. |
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Term
| What are the two unblocked openings to the middle ear. |
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Definition
One opens to the mastoid air cells in the mastoid process of the temporal bone.
The auditory tube, or eustachian tube opens in the pharnyx and allows air pressure to be equalized between the outside air and the middle ear cavity. |
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Term
| What is the bony labyrinth? |
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Definition
| A series of interconnecting tunnels and chambers within the temporal bone. |
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Term
| What is the membranous labyrinth? |
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Definition
| A smaller set of membranous tunnels and chambers within the bony labyrinth. |
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Term
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Definition
| A clear fluid within the membranous labyrinth |
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Term
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Definition
| A fluid within the space between the bony and membranous labyrinths. |
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Term
| What are the three regions of the bony labyrinth? |
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Definition
| Cochlea- hearing, vestibule and semi-circular canals- balance |
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Term
| What is the shape of the cochlea? |
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Definition
| The cochlea is shaped like a snail, with a bony core shaped like a screw |
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Term
| What are the spiral laminae? |
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Definition
| The "threads of the screw" |
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Term
| What are the three channels of the cochlea? |
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Definition
| Scala vestibuli, scala tympani and cochlear duct |
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Term
| Describe the scala vestibuli. |
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Definition
| A channel extending from the oval window to the apex of the cochlea. Filled with perilymph. |
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Term
| Describe the scala tympani. |
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Definition
| A channel extending parallel of the scala vestibuli from the apex of the cochlea to the round window. Filled with perilymph. |
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Term
| Where are scala tympani and scala vestibuli located? |
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Definition
| Between the walls of the bony and membranous labyrinths. |
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Term
| What is the vestibular membrane? |
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Definition
| The wall of the membranous labyrinth that lines the scala vestibuli. |
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Term
| What is the basilar membrane? |
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Definition
| The wall of the membranous labyrinth that lines the scala tympani. |
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Term
| Describe the cochlear duct. |
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Definition
| A duct formed by the space between the vestibular and basilar membranes. Filled with endolymph. |
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Term
| What is the spiral organ? |
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Definition
| A specialized structure in the cochlear duct containing specialized sensory cells called hair cells with hair-like microvilli on their surface. |
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Term
| What is the tectorial membrane? |
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Definition
| an acellular gelatinous shelf attached to the spiral lamina. the tectorial membrane is where the hair tips are embedded. |
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Term
| What is each hair cell associated with? |
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Definition
| Each hair cell is associated with the axon terminals of sensory neurons, the cell bodies of which are located in the cochlear ganglion. Axons form to join the cochlear nerve, which joins the vestibular nerve to become the vestibulocochlear nerve, which carrier axon potentials to the brain. |
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Term
Sound waves strike the (a) and cause it to vibrated.
Vibration of the (a) cases the (b-3) to vibrate.
The foot plate of the stapes vibrates the (c) |
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Definition
a- tympanic membrane
b-malleus, incus, stapes
c- oval window |
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Term
Vibration in the foot plate causes the (a) in the (b) to vibrate.
Vibration of the (a) causes the (c) to vibrate which causes birations in the endolymph. |
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Definition
a) perilymph
b) scala vestibuli
c) vestibular membrane |
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Term
Vibration of the endolymph causes displacement of the (a).
Short waves (high pitch) cause displacement of the (a) closer/higher (b) to the oval window. And vice versa. |
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Definition
a) basilar membrane
b) closer |
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Term
Movement of the basilar membrane is detected in the (a) of the (b) which are attached to the basilar membrane.
Vibrations of the perilymph in the scala vesibuli and of the basilar membrane are transferred to the perilymph of the (c) |
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Definition
a) hair cells
b) spiral organ
c) scala tympani |
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Term
| Vibrations in the perilymph of the scala tympani are transferred to the (a), where they are dampened. |
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Definition
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Term
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Definition
| A function of sound wave amplitude which causes the basilar membrane to distort more intesnely and the hair cells to be stimulated more strongly |
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Term
| What is conduction deafness caused by? |
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Definition
| Results from mechanical deficiences, for example, destruction of the ligament that holds the malleus and incus together. |
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Term
| What is sensorineural hearing loss caused by? |
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Definition
| Deficiencies in the spiral organ or nerves; for example, loud sounds can damage the delicate microvilli of the hair cells, leading to destruction of the spiral organ. |
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Term
| What is static equilibrium? |
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Definition
| Static equilibrium is associated with the vestibule and is involved in evaluating the position of the head, relative to gravity. |
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Term
| What is dynamic equilibrium? |
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Definition
| Dynamic equilibrium is associated with the semicircular canals and is involved in evaluating changes in direction and the rate of head movements. |
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Term
| What are the two chambers of the vestibule? |
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Definition
| The saccule and the utricle |
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Term
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Definition
| Specialized patches of epithelium located within each chamber of the vestibule, and surrounded by endolymph. The maculae contain hair cells similar to those of the spiral organ. |
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Term
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Definition
| Particles of protein and calcium carbonate floating within a gelatinous mass. The tips of the microvilli in each chamber sink into the otoliths. |
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Term
| What happens when we move our head? |
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Definition
| Hair cell microvilli bend in response to gravity and initiated action potentials in the associate neurons. Carried by the vestibular portion of the vestibulocochlear nerve to the brain where they are interpretted as a movement of the head. |
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Term
| How many semicircular canals are there, and how are they placed? |
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Definition
| There are three semicircular canals, each placed at right angles to eachother. |
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Term
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Definition
| The extended base of a semicircular canal. |
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Term
| What is crista ampullaris? |
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Definition
| The specialized epithelium within each ampula. |
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Term
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Definition
| The cupula is a curve gelatinous mass suspended over the crest of the crista ampula |
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Term
| What is the function of the crista ampullaris? |
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Definition
| As a person begins to tumble, the semicircular canals move in the same direction as the body. The endolymph in the semicircular canals tends to stay in place as the body and the crista ampullaris begin to move. As a result, the cupula is displaced by the moving endolymph in a direction opposite the direction of movement. |
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Term
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Definition
| The cupula is a curve gelatinous mass suspended over the crest of the crista ampula |
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Term
| What causes motion sickness? |
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Definition
| Continuous stimulation of the semicircular canals. Nausea and weakness caused when information to brain from semicircular canals conflicts with information from eyes and position sensors in back and lower limbs. |
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Term
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Definition
| The nmber of hair cells in the cochlea decreases, resulting in age-related sensorineural hearing loss. Does not occur equally in both ears. |
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Term
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Definition
| Phantom sound sensations, such as ringing in the ears; common problem. |
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Term
| What is middle ear infection? |
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Definition
| Symptoms are low-grade fever, lethaargy, irritability, and pulling at ear; in extreme cases, can damage or rupture tympanic membrane; common in young children. |
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Term
| What is inner ear infection? |
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Definition
| Can decrease detection of sound and maintenance of balance, may be caused by chronic middle ear infections. |
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Term
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Definition
| Vertigo, hearing loss, tinnitus and a feeling of fullness in the affected ear; most common disease involving diziness from inner ear; case unknown but may involve a fluid abnormality in ears. |
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