Senses Flashcards
What is Audition?
Sound: pressure waves generated by vibrating air molecules
What are the 4 major features of sound waves?
Waveform: Amplitude plotted against time
Phase
Amplitude: Usually in decibles. Loudness
Frequency: Expressed in Hertz. Pitch
What is molecular condensation?
It is also know as compression and it represents the displacement of molecules closer together
What is rarefaction
The displacement of molecules further apart
What are the 3 perceptual dimensions of sound?
Pitch: Determined by frequency
Loudness: Determined by amplitude and is a function of intensity
Timbre: Determined by the complexity of the sound. For example, the complexity expressed by different musical instruments
How do sound waves get transformed into neural activity?
- External and Middle Ears: The ears collect the sound waves and amplify the pressure to transmit to the inner ear, turning it from air to fluid.
- Inner ear: Once in the inner ear, the signal gets broken into simpler components. The hair cells transduce the frequency, amplitude and phase. Then, the auditory nerve fibers encode the electrical activity.
What is the pinna?
Part of the outer ear. It collects and alters the reflection of sound waves into the middle ear. It also helps locate the source of a sound.
Other parts of the outer ear include the concha and the auditory meatus (ear canal)
What structures are in the middle ear?
Tympanic membrane
Ossicles
Malleus
Incus
Stapes
Oval Window
What does the tympanic membrane do?
Vibrates at the same rate when struck by sound waves and is connected to teh ossicles
What are the ossicles and what do they do?
The ossicles transform waves into stronger waves
The 1st is the malleus “hammer”
The 2nd is the incus “anvil”
The 3rd is the stapes “stirrup”
What is conductive hearing loss?
Damage to the external inner, or middle ear
What is sensorineural hearing loss?
Damage to the inner ear
What is impendance matching?
Matching of airborne sounds to acoustic waves traveling in fluid of inner ear. This boosts the pressure from the big tempanic membrane through the small oval window. Then the ossicles perform a lever action.
What is the oval window?
A membrane of the inner ear
The stapes presses against it to transmit sound waves into the viscous fluid within the cochlea
What structures are in the inner ear?
Cochlea
Organ of Corti
Scala vestibuli, tympani, & media
Basilar Membrane
Tectorial Membrane
Hair cell
Round Window
What is the cochlea?
It is a snail shaped structure that contains auditory transducing mechanisms. It amplifies sound waves and converts them to neural signals. It also decomposes complex waveforms
What is the Organ of Corti?
It is the receptive organ of the cochlea. It sits on the basilar membrane and contains auditory hair cells. It is the transducer
What are the scala vestibuli, the tympani, & the media?
They are the fluid filled chambers of the cochlea
What is the basilar membrane?
It is a membrane in the cochlea of the inner ear that contains the Organ of Corti
What is the tectorial membrane?
It is located above the basilar membrane and serves as a shelf against which cilia move
What is an auditory hair cell?
It is a receptive cell that lies between the basilar membrane and the tectorial membrane in the cochlea. When hair cells become displaced by vibrations in the fluid of the cochlea, they excite the cells of the auditory nerve.
What is the round window?
An opening of the bone in the cochlea. It vibrates in the opposite phase to the vibrations entering the inner ear. It permits vibrations that are transmitted through the fluid in teh cochlea.
How does the basilar membrane tune frequency?
The physical characteristics of the basilar membrane help to tune the frequency. The wider, more flexible part is at the end, making for a lower sound. The base is more narrow and stiff, making for a higher sound
How does sound travel in the inner ear?
The stapes vibrates against the membrane of the oval window, which makes sound waves to the cochlea
Vibrations cause the basilar membrane to flex
Pressure changes in the fluid underneath the basilar membrane are transmitted to the membrane of the round window
The round window moves in and out - opposite of the oval window. As the stapes pushes in, the round window bulges out
What is cilium
Hair-like appendages of the cell involved in movement or sensory transduction
What is the tip link?
An elastic filament that attaches to the tip of one cilium to the side of an adjacent cilium
What is an insertional plaque
Point of attachment of a tip link to cilium