~Chapter 11 - Lecture Section 11.2 Flashcards
What are the parts of the Outer Ear?
The Pinnae, the Auditory Canal, and the Tympanic Membrane (eardrum)
What are the parts of the Middle Ear?
The Ossicles, the Oval Window, and the Middle Ear Muscles
What are the parts of the Inner Ear?
The Cochlea
Which part of the Ear holds up our glasses?
The Pinnae
The shape of the ___ is important for sound localization
Pinnae
Does the Pinnae play a role in transduction?
Not a large one, no
True or False: The length of the Auditory Canal is important
True
The sound waves that are reflected off of your ___ create ___ interference with incoming waves, such that sound in the range of ___Hz is amplified.
eardrum (the Tympanic Membrane) // constructive // 2,000-5,000
Where is the Tympanic Membrane (Eardrum) located?
At the very end of the Auditory Canal
Which part of the Ear serves as the border between the Outer and Middle Ear?
The Tympanic Membrane (Eardrum)
The Middle Ear consists of an ___ and ___ structures.
air-filled chamber // amplification
What are the Ossicles?
Malleus (Hammer), Incus (Anvil), Stapes (Stirrup)
Where are the smallest bones in the human body located?
In the Middle Ear. They are the Malleus (Hammer), Incus (Anvil), and Stapes (Stirrup)
The ___ connect the Tympanic Membrane to the ___.
Ossicles // Cochlea
How were the Ossicles named?
They are named after their shape
What is the job of the Ossicles?
Their job is to amplify sound-waves
The Ossicles are associated with the ___.
Middle Ear Muscles
Where are the smallest skeletal muscles in the human body located?
In the Middle Ear, they are the Middle Ear Muscles
What is the job of the Middle Ear Muscles?
Their job is to dampen vibration at the Ossicles at high intensities
As sound-waves are pressing onto the Tympanic Membrane, there is vibration that is transmitted through the Ossicles, and it pushes onto the ___ of the Cochlea.
Oval Window
The ___ is filled with fluid, so it cannot compress, and so whenever the ___ pushes in on the ___, the ___ pops out.
Cochlea // Stapes // Oval Window // Round Window
There are ___ ways that the Ossicles cause physical amplification in the Middle Ear
2
What is the first way that the Ossicles cause physical amplification in the Middle Ear?
The Tympanic Membrane has a much larger surface area than the surface area of the Stapes foot plate, therefore the Ossicles concentrate the vibration onto a much smaller surface area which increases the sound-pressure level by a factor of 17.
What is the second way that the Ossicles cause physical amplification in the Middle Ear?
By acting as levers, a bit like a teeter totter, and this increases vibration by a factor of 1.3P
Why is Physical amplification of sound by the Middle Ear required?
Because pressure changes in the air (Outer and Middle ear) are transmitted poorly to liquid (the Cochlear fluid) and so it requires amplification in order to make those sound vibrations large enough to produce Transduction.
Why do some fish not have Outer and Middle Ear structures?
Because they do not need to amplify sounds as greatly since water and Cochlear fluid have similar densities, both the Outer and Inner areas are both fluid-filled.
When you listen to sound underwater, that dampening is what’s being overcome by the amplification in the ___.
Middle Ear
What are the physical characteristics of the Cochlea?
In its natural state, the Cochlea is a spiral-shape.
The Cochlea is about 2mm x 35mm
Pressure changes produced by the movement of the Stapes creates vibrations that are transmitted to the fluid, and so the ___ that are impinging on the Tympanic Membrane through the amplification by the Ossicles, and this spiral-nature of the Cochlea set up ___ in the ___.
longitudinal waves // transverse waves // Basilar Membrane
Is the Cochlea an air-filled or fluid-filled structure?
Fluid-filled structure