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25 Cards in this Set
- Front
- Back
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Two parts of the outer ear |
auricle or pinna and external auditory canal |
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Function of outer ear |
resonating and collecting sound, protecting the middle and inner ear. |
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What is the external auditory canal? |
Cartilaginous s-shaped tube that travels from the pinna to the tympanic membrane. |
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What are the parts of the pinna or auricle? |
helix (superior), antihelix (medial), concha (inferior), tragus (entrance) |
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What does the auricle or pinna function as? |
Allows sound to travel through the ear canal and allows us to pinpoint the location of an incoming sound. |
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What are the parts of the middle ear? |
tympanic membrane, ossicular chain (malleus, incus, stapes), eustacian tube |
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What is a common problem of the eustachian tube? |
Fluid and other germs can be transmitted from the nasopharyngeal cavity to the middle ear, thus causing inner ear infections. |
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What is the tympanic membrane? |
An elastic membrane which vibrates to sound pressure and triggers the ossicular chain. It also turns the acoustic energy of the sound into mechanical energy. |
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What is a function of mediums in the tympanic membrane? |
Regulates between air vibrations from the outside to the fluidic vibrations of the inner ear. |
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What is the ossicular chain? |
Contains malleus, incus, and stapes. Malleus is shaped like a hammer and attached to tympanic membrane and incus. Incus is attached to the stapes, which is connected to the oval window which ultimately connects to the cochlea. |
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What is the eustachian tube? |
Tube that connects nasopharynx with middle ear. Its function is to maintain air pressure between outside and middle ear. Activated by yawning. |
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What are the parts of the inner ear? |
Contains a temporal bone which holds the parts of the inner ear in a perilymph fluid. Vestibular system has three semicircular canals. Cochlea is a snail-shaped coiled passage. |
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What is the vestibular system? |
Vestibular system has three semicircular canals that are responsible for maintaining equilibrium. Contains anterior, posterior, and horizontal canals. |
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What is the cochlea? |
Filled with endolymph and contains the basilar membrane and the organ of Corti. Initially changes mechanical energy into hydromechanical energy and then into electrical energy to be sent to the brain. |
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What are the parts of the cochlea? |
organ of Corti, arch of corti, modiolus, stria vascularis |
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What is the organ of Corti? |
Contains thousands of hair cells called cilia. They respond to sound. |
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What are the outer and inner hair cells? |
Outer - three to five rows that respond efferently Inner - one row that responds afferently |
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Where are sounds responded to in the cochlea? |
Low frequency sounds are heard at the top or tip of the cochlea while high frequency sounds are heard toward the base. |
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What is beyond the inner ear when it comes to sound transmission? |
The auditory nervous system. |
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What is the auditory nervous system? |
Contains the acoustic nerve (VIII) that takes electrical energy from cochlea to the brain. |
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What is the vestibular branch? |
Focuses on maintaining equilibrium and supplying hair cells of the cochlea. Transmits sound to the brain. |
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How do hair cells in the cochlea transmit sound to the brain? |
With the perilymph fluid being disrupted in the cochlea via the movements of the stapes in the oval window, the hair cells detect the disruption and transmit to individual nerves (over 30,000 of them) that eventually go to the brain. |
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What is the path taken from the cochlea to the brain? |
Starting out as peripheral to the brain at the brainstem and becoming central as they pass the brainstem, the impulses cross over to the other side of the pathways, thus becoming contralateral. |
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What part of the brain is responsible for receiving sound? |
The temporal lobe |
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How does the temporal lobe process sound? |
The nerve impulses project sound to the temporal lobe, which can then process and interpret it. |
