Lab 5

Question 1

3 ossicles of the inner ear

Answer 1

MIS malleus, incus, stapes

Question 2

list flow of sound to brain

Answer 2

sound –> ear canal –> tympanic membrane –> 3 ossciles –> oval window –> vibration of fluid in cochlea –> round window aids vibration –> hair cells vibrate –> mechanically gated ion channels open –> AP generated to cochlear nerve –> cranial nerve 8 to brain

Question 3

name of nerve carrying sound to brain

Answer 3

cranial nerve 8 = vestibular cochlear nerve

Question 4

purpose of ossicles

Answer 4

amplify vibration caused by sound - especially stapes

Question 5

name of middle ear infection, why, and what it can cause

Answer 5

otitis media, eustachian/auditory tube conncts pharynx to middle ear so upper respiratory infections can easily lead to middle ear infections

Question 6

vestibular apparatus

Answer 6

sends information about relative body position of the entire body

Question 7

Rinne test how to do

Answer 7

strike tuning fork –> hold against mastoid process of temporal bone –> wait until sound no longer heard –> hold near ear and ask if sound is still heard

Question 8

positive Rinne test and meaning

Answer 8

normal! air conduction > bone conduction, sound is heard when bringing it to ear

Question 9

negative Rinne test and meaning

Answer 9

abnormal, sound is not heard again after bringing it to ear, indicates conductive hearing loss

Question 10

conductive hearing loss meaning and causes

Answer 10

air conduction < bone conduction, problem with outer ear, middle ear, oval or round window and vibrations

Question 11

webers test how to do

Answer 11

hit tuning fork –> place on top of skull –> see if sound is conducted through bone evenly on both sides

Question 12

lateralization of webers test meaning

Answer 12

right/left lateralization means sound is heard LOUDER on that side

Question 13

2 explanations for lateralization in webers

Answer 13

• ear that hears louder has conductive hearing loss (sound gets trapped, background noise is cancelled, ear becomes more sensitive to bone conduction)
• sensorineural hearing loss on quieter side

Question 14

weber lateralized to the right and Rinne negative on the right

Answer 14

conductive hearing loss on right

Question 15

Weber no lateralization and Rinne positive bilaterally

Answer 15

normal or sensorineural hearing loss equal on both sides

Question 16

weber lateralized to the right and Rinne positive bilaterally

Answer 16

sensorineural hearing loss on left

Question 17

weber no lateralization and Rinne negative bilaterally

Answer 17

conductive hearing loss on both sides

Question 18

cochlear implant - how it works and what it treats

Answer 18

generates electrical signals, treats conductive hearing loss although cochlear nerve still has to work, mimics hair cells which generate AP

Question 19

hearing aid - how it works and what it treats

Answer 19

makes sound louder, treats conductive hearing loss

Question 20

24 year old who listens to loud music - what type of hearing loss?

Answer 20

sensorineural hearing loss

Question 21

child with otitis media and hearing loss - what type of hearing loss

Answer 21

conductive hearing loss

Question 22

pathway of light through 3 main parts of the eye

Answer 22

light –> pupil –> lens –> retina

Question 23

visual acuity

Answer 23

sharpness and clarity of the image

Question 24

myopia

Answer 24

nearsightedness, eye ball is too long, image falls in front, object must be brought closer to see

Question 25

hyperopia

Answer 25

farsightedness, eye ball is too short image falls behind, object must be brought further away to see

Question 26

presbyopia

Answer 26

caused by old age, lens is not flexible enough so accommodation to see close object fails, reading glasses needed

Question 27

accommodation

Answer 27

ability of eye to change curvature of lens to see close/far objects clearly

Question 28

astigmastism

Answer 28

abnormal curvature of lens, creates distorted vision, also corrected with glasses

Question 29

20/40 meaning

Answer 29

you see clearly at max 20 feet what others see clearly at max 40 feet

Question 30

snellen chart - how to do

Answer 30

person stands 20 feet away, read line with one eye at a time then both

Question 31

blind spot cause

Answer 31

optic nerve leaves at optic disc, no photoreceptors there

Question 32

why are we not aware of blind spot

Answer 32

small, located at peripheral vision, brain join eye from both eyes and resolves the blind spot

Question 33

2 point discrimination / threshold test - how to do

Answer 33

caliper with 2 points, decrease distance until only 1 point can be felt

Question 34

meaning of 1 vs 2 point felt

Answer 34

1 point = points are on same receptor field, 2 points = on different receptor fields

Question 35

purpose of 2 point discrimination test

Answer 35

measure receptor density

Question 36

referred pain meaning

Answer 36

pain from an internal visceral organ is felt in another region of the body

Question 37

cause fo referred pain

Answer 37

sensory neurons from visceral organ and other body parts synapse with the same interneuron so brain can’t distinguish the location its coming from

Question 38

angina pectoris

Answer 38

heart pain/damage felt in chest wall or shoulder

Question 39

phantom limb pain

Answer 39

amputation –> postcentral gyrus and sensory neuron cell body in spine still alive –> temperature, touch, stress activates neurons causing pain that seems to come from amputated limb

Question 40

otosclerosis

Answer 40

calcification of ossicles caused by repeated otitis media, leads to conductive hearing loss