Card Set Information
What are the components of the external ear?
external acoustic meatus
- surrounds entrance to external acoustic meatus
- protects opening of canal
- provides directional sensitivity
external acoustic meatus
ends at tympanic membrane (eardrum)
is a thin, semitransparent sheet
separates external ear from middle ear
Explain the middle ear.
auditory ossicles (malleus, incus, stapes)
- convert pressure fluctuation in air into much greater pressure fluctuations in perilymph of cochlea
frequency of sound
Frequency of sound
determined by which part of cochlear duct is stimulated
determined by number of hair cells stimulated
Vibration of Tympanic Membrane
converts arriving sound waves into mechanical movements
auditory ossicles conduct vibrations to inner ear
tensor tympani muscle
What does the tensor tympani muscle do?
stiffens typanic membrane
What does the stapedius muscle do?
reduces movement of stapes at oval window
Explain the cochlea of the inner ear?
-contains cochlear duct (elongated portion of membranous labyrinth)- receptors provide sense of hearing
Explain the round window of the inner ear?
thin, membranous partition
separates perilymph from air spaces of middle ear
Explain the ovalwindow of the inner ear?
formed of collagen fibers
connected to base of stapes
Effects of Aging on the Ear
with age, damage accumulates
- tympanic membrane gets less flexible
- articulations between ossicles stiffen
- round window may begin to ossify
What does the internal ear contain?
contains fluid called endolymph
bony labyrinth surrounds and protects membranous labyrinth
: vestibule, semicircular canals, cochlea
Explain the vestibule of the inner ear?
encloses saccule and utricle
receptors provide sensations of gravity and linear acceleration
Explain the semicircular canals of the inner ear?
contain semicircular ducts
receptors stimulated by rotation of head
sensations provided by receptors of vestibular complex
- basic receptors of inner ear
- provide information about direction and strength of mechanical stimuli
Explain the semicircular ducts
are continuous with utricle
each duct contains:
- ampulla with gelatinous cupula
- associated sensory receptors
- stereocilia--resemble long microvilli
--- are on the surface of hair cell
Explain the utricle and saccule
- oval structures where hair cells cluster
Explain the ceruminous glands
integumentary glands along external acoustic meatus
secrete waxy material (cerumen)
- keeps foreign objects out of tympanic membrane
- slows growth of microorganisms in external acoustic meatus
__ causes the ear to vibrate [like a flickering flame on a candle]
__ acts as a __ to funnel that air in to hit that __.
outer ear (pinna--or--oracle)
The bones are attahced to each other and are _, hanging like a motor vehicle. They act as __ that __ the sound to allow it to go over to the __.
What will levers do?
The stapes is literally attached to the __, which is another membrane that separates the __ from a portion of the __.
inner ear (vestibular canal)
__ is inside of the inner ear.
__ of the 206 bones in the body are in the ears.
The oval window is not even __ the size of the __.
The __ is impeding on the __, which sets in motion the fluid of __.
How do we perceive frequencies?
by the distance of the first wave from the oval window
humans can get up to 20,000 range
The closer it is to the oval window, the what?
higher the frequency is
The structure of the human ear
- The hair cells are __.
- you are opening channels; there are channels in between these __ that, when the wave comes through, __.
stereo cilia (papercuts)
ions trickle, creating EPSPs
The inner ear is also important for __ and __.
balance and equilibrium
What is the vestibular canal?
the fluid you set in motion
Wave = ?
distortion happening and pressing on the middle canal, the cochlear duct
True or False:
You can detect velocity.