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173 Cards in this Set
- Front
- Back
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list the four functions of the ear
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1. transducer- changes one form of energy to another.
2. amplifier- info that ear receives, must be increased in volume in order for us to perceive it. 3. analyzer-analyzes characteristics (pitch) that it receives 4. intergrator- must process everything in receives and send it to the brain |
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list the five main sections of the ear
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1. outer ear(external ear)
2. middle ear 3. inner ear 4. 8th Nerve (auditory nerve) 5. central auditory system |
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how many peripheral systems do we have
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2- one on each side
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how many auditory nerves do we have
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2
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how many central auditory systems do we have
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one
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where in the skull is the ear locatd
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the temporal bone of the skull
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all structures of the ear are either in or attached to the
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temporal bone
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list the four sections of the temporal bone
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1. squamous- flat portion, right above external ear canal
2. mastoid bone- many air filled cavities (pockets) 3. tympanic portion- below ear canal 4. petrous portion- hardest, most dense, provides protection. houses balance system |
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does the inner or outer ear develop first
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develops from inner ear outward
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at what week does the inner ear start to develop
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3rd week
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what is seen in the ear at the 5th week
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start to see difference between balance system (semi-circular canals) and cochlea
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what is seen at 4th month of gestation
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cochlea is completely developed and looks like adult structure
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at what age does the middle ear start to develop
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starts to dev. at 4th week
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at what month is the inner ear finished dev.
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at 4 months
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what happens when inner ear is finished dev.
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middle ear cavity (opening) develops at that point
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what begins to develop after the middle ear cavity develops
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middle ear bones will begin to develop
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what happens at the same time that the middle ear bones are developming
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the external ear canal starts to form
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what happens at 5-6 months
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outer ear starts to look how it should
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what happens at 7 months
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ear canal finishes forming. outer ear looks like adult structure and ear canal opens so they can hear very well
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what are two other names for the outer ear
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auricle, pinna
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what is the outer ear made of
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cartilage
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what is the function (list three)
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1. collects sound.
2. helps localize where sound is comign from 3. helps keep foreign objects from getting into ear |
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what is another name for ear canal
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external auditory canal (meatus)
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is the EAC horizontal or verticle
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horizontal
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what shape is the EAC
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oval
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how many cm long (adult length is the EAC
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2 1/2 cm
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what is at the end of the EAC
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ear drum
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what is another name for the ear drum
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the tympanic membrane
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what is the first 1/3 of the cana made of
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cartilage
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what is the name of the stiff hairs found in the ear canal and what is their purpose
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cilia, keeps things from getting in the ear. also keeps wax moving out of ear.
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what kind of glands are found in the inner ear and what is its purpose
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glands that secrete a bitter substance (ear wax) cerumen. keeps foreign objects out of ear.
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what is the second 2/3 of the canal made of
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osseous, boney structure
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what are the two functions of the ear cannal
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1. direct sound to ear drum (tympanic membrane). due to shape it has a resonance (sound boosting) boosts high frequency sounds. little kids boost high frequency sounds even higher.
2. discourage bacteria or foreign objects from getting in. cerumen can cause hearing problems that can be fixed by removing wax. |
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what is the shape of the middle ear
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wedge shaped, but everyone is different
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what is the middle ear cavity filled with
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air filled. open to ear cells in mastoid
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is the middle ear open to the outside
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open to outside through throat.
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what does the tympanic membrane seal
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seals ear off from outside
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where is the tympanic membrane found
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beginning of middle ear
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what is the tm made of
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tight place of skin made of several layers of tissue .
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how do you view the middle ear
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by looking at tm with an ottoscope
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when looking at the tm what part of it are you looking at
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at the back of the tm
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what does a normal tm look like
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looks gray and translucent. cone shaped. cone of light (reflextion of ottoscope)
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is the edge or center portion of the tm more flexible
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very tight around rim (edge). center portion is much more moveable.
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what are characteristics of an unhealthy ear drum
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will have bubbles behind it. redness. looks sucked in (problem with middle ear pressure)
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function of ear drum
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vibrates, moves sound along, seal off middle ear, protective
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what are the auditory ossicles?
List? |
middle ear bones
1. malleus 2. incus 3. stapes |
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which of the three bones is imbedded in the tm
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the head of malleus is imbedded and attached to the eardrum. so when air comes in a vibrates TM then vibrates malleus which is attached on the other side to the incus which is attached to the stapes.
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which bone is the smallest in the whole body
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the stapes.
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where does the stapes attach
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attaches to oval window of inner ear.
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describe the amount of movement of the stapes
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moves more than other bones-more articulation. moves back and forth. also pivots.
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can middle ear bones break
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yes
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where is the oval window found and where does it open up to
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part of middle ear but opens into the cochlea.
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what does the oval window do with energy
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sends energy to inner ear. this is where you transition from mechanical energy to a hydrodynamic energy (liquid)
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what is found below the oval window
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round window.
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describe the relationship between the oval and round window
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the round window compliments the oval window. oval window pushes liquid in round window releases (outlet) (gives it space) (pressure valve)
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of what structure are the oval and round window found on the outer edge
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on outer edge of cochlea
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what does the eustachian tube connect
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middle ear nasopharynx.
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what is the difference between the angle as an adult and the angle as a child
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the angle as an adult is very verticle. the angle as a child is more horizontal. this is the reason for so many ear infections as a child.
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for how many months of life is the tube open
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first 16 months
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at what age is the tube vertible enouch so have few ear infections
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at age 8
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function of the eustachian tube
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provides access to outside ear. equalizes pressure.
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how often does the eustachian tube open
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once per minute when awake. once per five minutes when asleep.
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what happens if hte eustachian tube is not working correctly
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there will be pressure build up in ear
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what are the two middle ear musclese
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1. tensor tympani
2. stapedious |
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what does the tensor tympani do
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react to loud stimulation coming into the ear pulls back on ear drum
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what does the stapedious muscle do
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reacts to lound stimulation coming into the ear. caused to rock when the tensor tympani pulls back on ear drum.
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which of the two muscles is more effective
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stapedious
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what is the purpose of the two muscles
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the two muscles work together to protect ear from damage due to a loud sound. they interupt sound.
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does the process of the two muscles work that well? what are the limitations
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no.
1. contraction takes time. if gun shot sounds rapidly these wont protect from that. the muscles don't move fast enough. 2. won't work with long term protection. if at a concert- the muscles will fatigue |
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what is the physiological function of the middle ear
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amplification of accoustic energy that comes i.
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what is the percentage of sounds that comes into the ear that is lost
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99%
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describe the process of compensation for all the lost sound
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middle ear bones vibrate in order to amplify. this exerts more pressure on oval window. the stapes is slammed into the oval window.
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why does this process work so well (volume area)
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goes from a big volume are (ear drum) to small area. the energy is very strong when going into the small area. more pressure at small portion.
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what are the three basic divisions of the inner ear
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1. vestibule
2. semi-circular canals 3. cochlea |
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which of these divisions is in the beginning of the inner ear and is the main entrance.
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vestibule
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what does the vestibule allow access to
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to all parts of inner ear
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where does the vestibule start
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at oval window
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what is the vestibule filled with
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with fluid called perilymph. it is a clear and watery looking fluid. it surrouds everything
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what two things does the vestibule contain
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1. utricle
2. saccule |
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what are the utricle and saccule surrounded by
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perilymph
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what are the utricle and saccule
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sensory organs of balance
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what are the utricle and saccule filled with
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endolymph (watery fluid)
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what is found inside these sensory organs
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maccula
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what is the job of maccula
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says how we're moving our head-forward, backward, side to side. fibers in the maccula that sends the info about where our head is to the brain.
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second division, semi-cirular canals. what is the job?
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helps with balance and equilibrium of whole body.
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how many canals are found inside the semi-circular canals
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3.
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cristaamplularis-what is it? what does it do?
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little beds of hair cells found inside each canal. send information to brain about overall balance.
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information fromt eh sensory organs and the hair cells are sent to the brain by
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the vestibular portion of the8th nerve. this nerve leads to the brain
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division 3-cochlea-physical characteristics
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snail shaped. hard structure. protective. a tube that is fatter at the beginning, twirls around and is narrow at the tip.
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how many times does the cochlea twirl
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2 1/2 times
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what is the name of the center of the cochlea and what comes out of it
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mediouls- circular tube. nerve endings come out of this
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cochlea is the organ of___
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hearing
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what are the three sections of the cochlea
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1. scala vestibuli
2. scala media 3. scala tympani three tubes that make up the cochlea |
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where does the scal vestibuli start
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at the oval window
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what is the shape of the scala media
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triangular shaped-not tube shaped.
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what is another name for scala media
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cochlea duct
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which of the three parts of the cochlea is a sealed tube at the center of the cochlea that does not open to anything
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scala media
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where does the scala tympani start
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ar round window
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what are the two dividers of the scala tympani
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1. rissner's membrane
2. basilar membrane |
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what does the rissner's membrane divide
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scala vestibuli and scala media
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what does the basilar membrane divide
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the scala media and scala tympani
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where does much info aobut tones get sent to the brain from
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basilar membrane
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what is each tube of the cochlea filled with
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-scala vestibuli filled with perilymph
-scala tympani filled with perilymph -scala media filled with endolymph |
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how many fibers does the basilar membrane contain
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20-24 thousand fibers that help send info to the brain about what we hear.
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shape of basilar membrane
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starts out wide and then gets skinnier as it goes along
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describe the chain reaction
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when stapes hits oval window it causes fluid to move in scala vestibuli-> this causes risner's membrane to move-> causes basilar's fluid to move over it-> wiggling fibers
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what part of the basilar membrane vibrates with high frequency
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the wider part of the membrane vibrates
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what part of the basilar membrane vibrates with low frequency
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the whole membrane vibrates
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which do older people think people don't speak as clear as they used to
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consonant sounds are high pitched. high pitched sounds only vibrate on the wider part of the membrane, which is the part that wears lout first. since it wears out first, people loose that hearing first.
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what is the name of hte organ that is found on the basilar membrane
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organ of corti
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what is the organ of corti
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place where we make the conversion between fluid into electrical stimulation (energy)
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what are the two parts of the organ of corti
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1. inner portion
2. outer portion |
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what does the inner portion house
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houses inner hair cells.
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what is the job of the inner hair cells
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receptor cells for tones.
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how many rows of inner hair cells is there
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one row
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describe the texture of the inner hair cells
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very stiff- very resistant
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how many rows of outer hair cells are there
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3 rows.
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describe the texture of the outer hair cells
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very flexible
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where does the inner portion of hte organ of corti send information and how do we know?
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have all afferent nerve fibers. meaning they send info to the brain
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where does the outer portion of the organ of corti send info and how do we kno
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have more efferent nerve fibers which menas it sends info out to middle ear
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what is located on the outer hair cells that help to send then info on?
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sterio cillia
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what is the organ of corti covered by
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the tectorial membrane
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what does the tectorial membrane do
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sends frequency information to the brain
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all information that goes through the cochlea ends up at
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many nerve endings
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how many neurons does the cochlea have that sends info
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32000
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whawt are the three components contained in the auditory neuron(part of auditory nerve fiber)
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1. cell body
2. dendrites 3. axon |
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list two characteristics of the cell body
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contains the nucleus of hte cell. responsible for keeping neuron going.
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what are two characteristics of dendrites
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receptors of chemical information from cochlea for organ of corti. generates electrical current
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what does the axon connect to
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to the dendrite
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what does the axon carry
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electrical impulse that dendrite ahas given it and sends it along
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how does the axon send the info
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via synapse. neurons don't touch.
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what is synapse
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the space between the dendrites
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what does the concept of resonant frequency say
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states that the cochlea was full of tiny resonators and each one was tuned to a specific frequency.
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what was imp about the person who thought up this theory
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he was the first to look at the placement of frequency on the cochlea
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what does place theory say
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atribued all analyses of pitch to the cochlea and our brain had little to do with it. thought the cochlea was like a piano keyboard
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traveling wave theory
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1960. bekesy. one that many people follow today. inward and outward movement of stapes causes movemetn (wave of fluid) of Basialr membrane. the high frequencies were stimulated at the beginning and low frequencies stimulated all the way along. the signal determines the distace of the traveling wave high frequency- shorter distance.
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frequency theory
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newer theory. pitch analysis does not take place in cochlea. happens beyond the cochlea. the auditory nerve sends a signal to the brain that corresponds exactly with the imput. 100Hz tones comes into ear then auditory nerve fires 100x a second. what comes in is exactly what is sent in. not true because it doesn't eexplain how we can hear high frequency info. 400Hz is very low pitched.
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volley theory of hearing
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the auditory nerve receives a group of impulses and can do several things. with certain sounds certain neurons fire and some rest. volley back and forth. some vollying while others are not.
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another name for 8th nerve
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vestibulocochlear nerve
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where does the 8th nerve bring info from
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getting info from vestibular system and cochlea
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what are the two parts of the 8th nerve
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1. vestibula portion
2. auditory portion |
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vestibula portion
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portion that gets info from balance system. sensory cells in semi-circular canals provide info to vestibular portion of system
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auditory portion of nerve
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portion of nerve is what gets the info from hair cells that have sent the info to nerve fibers. bundle together toward end of throughthe medialous and head up to brain
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in the bundle...what part os high frequency and what part is low frequency
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outer portion is high frequency and inner portion is low frequncey
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is the facial nerve part ofhte auditory portion or vestibular portion
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audiotry portion. facial nerve runs along ear canal. gathers right near the auditory fibers
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the nerve comes together (both parts of the 8th nerve) and goes where
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enters the brain at the medula (or Cerebello-pontine angle) same place.
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what happens to the nerve after it hits the cpa
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splits again
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where are the two place the nerve descends to
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1. dorsal cochlear nucleus
2. ventral cochlear nucleus |
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dorsal and ventral cochlear nucleus are much like the
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cochlea
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which of the dorsal ventral cochlear nuclei are tonotopic and what does that mean
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they both are. specific frequency arranged according to frequency. certain locations deal with high frequency and other with low frequency.
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where does the auditory nerve come from and where does it end
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come from the cochlea and ends in the cochlea nuclei
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decussations
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cross over points. since we are symmetrical. need connection between one side of brain and the other
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commissure
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how info moves on the same side from location to location
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what is the name of the first place after the cochlear nuclei that information will pass through
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trapezoid body
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from the ventral cochlear nuclea teh auditory imput travels ipsilaterally to the
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superior olivary complex
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at the same time send info contralaterally to the
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superior olivary complex
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lateral lemniscus
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only gets info ipsilaterally. have some frequency specific characteristics. tonotopic
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inferior colliculus gets info from _______ ipsilaterally
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lateral lemniscus
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inferior colliculus also gets info from the
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dorsal cochlear nuclei
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the inferior colliculus sends info
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back and forth
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what is the name of the last relay station of information
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medial geniculate body
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do nerve fibers fan out or are they neat
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fan out
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where does the info go from the medial geniculate body
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the auditory cortex. (area of auditory perception) last stop
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is the auditory cortex tonotopic?
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yes
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what are the three areas of the auditory cortex
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1. temporal area
2. insulor area 3. parietal area |
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what does the temporal area deal with
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primarily looking at frequency characteristics of info
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what does the insulor area deal with
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temporal aspects of info it gets-related to timing
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what does the parietal area deal with
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has to do with sound associated with past experiences. hear a song and it makes you think of something.
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descendign fibers follow a ________ pathway that it took to ascend
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similar
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many fibers that come down end up at the (big area) ______ (more specified area) ________
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pons. olivocochlear bundle
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this bundle of all the fibers sends its fibers back to the
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cochlea
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what do they think is the purpose of sending it back to the cochlea
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they think it supresses or queits the organ of corti
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what are the two theories of why it would want to supress the organ of corti
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1. think it may help when we're around a lot of back ground noise
2. helps conserve energy in organ of corti to help it function better with new stimulation. |
