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53 Cards in this Set
- Front
- Back
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What are the three main sections of the ear?
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Outer
Middle Inner (cochlea) |
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What is the frequency range discernible by the human ear?
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20 - 20,000 Hz
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What is the freq range for normal conversation?
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500 - 3000 Hz
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What is sound intensity and how is it measured?
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the volume or "loudness"
measured in decibels (dB) |
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What are some symptoms of noise fatigue?
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headache, nausea, distraction, irritable
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What is tinnitus?
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It is a delayed onset "ringing" in the ear(s) - no pain
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What are three characteristics of vibration?
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Frequency
intensity duration |
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What results from prolonged vibration?
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Discomfort, muscle tension, visual acuity, distraction, fatigue
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What is "conductive" hearing loss?
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Purely mechanical, meaning a "broken" ear drum or ossicles (bones)
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What is the term for hearing loss that is characterized by an impairment of the cochlea and/or auditory nerve?
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Sensorineural loss
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To what extent of intensity are both ear plugs and headsets estimated to protect hearing?
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Ear plugs - 33 dB reduction
Headset - 24 dB reduction |
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Regarding audiograms, what amount of decibels "lost" is considered significant?
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20 dB
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Vision is __% of orientation
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90
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Visible light is a (small/large) part of the spectrum?
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small
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Explain the primary function of each of the following parts of the eye:
Cornea, Lens, Iris |
Cornea: gather and refract light
Lens: focus on the retina Iris: controls amount of light that enters |
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Explain the primary functions of the retina and the optic nerve
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Retina: the "photographic film"
Optic Nerve: causes natural blind spot |
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Describe what cones are essential for, and whether they are photopic or scotopic
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Bright lights/colors, daytime vision, detailed central vision
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Describe what rods are essential for, and whether they are photopic or scotopic
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low light vision, B&W, movement, and peripheral vision
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In relation to acuity, what are the correct terms for nearsightedness and farsightedness, respectively?
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Myopia and Hyperopia
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What acuity problem is associated with old age?
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Presbyopia
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What is astigmatism?
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unequal curvature of the lens and cornea
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Does the FAA require eyes to be corrected EQUALLY?
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yes...
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What chemical is building up during "dark adaptation"?
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Rhodopsin
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Name 4 factors that effect vision
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1) Low grade hypoxia
2) CO 3) Fatigue 4) Alcohol |
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How is red light used without ruining night vision?
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the red wavelength does not stimulate the RODS
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What method can we use to counteract the fact that there are no ____ in the foveas?
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Off-center viewing (scanning 10 degrees around object)
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What does "scanning" help compensate for?
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Night blind spot, natural blind spot, space myopia
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Describe space myopia
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Like a gray sky, no stimulation beyond 20 ft = lens tends to just rest
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______ prevents _____ ______, which is a "bleaching out" of retinal cells, leaving a ghost image
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Scanning; retinal burnout
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What is autokinesis?
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An apparent movement of a stationary source of light
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____ perception and _____ determination are compromised at night
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Depth , distance
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Spatial disorientation is usually related to the _______ system
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vestibular
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Flying by the seat of your pants is a form of ________ disorientation
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postural
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the type of disorientation characterized by vertigo etc is?
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Vestibular dis... (source of most motion sickness problems)
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Re the inner ear, what do the semicircular canals sense?
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Angular acceleration (like 3 gyros)
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What do the otilith organs sense?
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linear acceleration and gravity
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In the semicircular canals, what is bent by movement to stimulate the vestibular nerve?
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Cupula
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When is the coriolis illusion most likely to take place?
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When in a constant rate turn and you move head into another plane of rotation
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What effect is characterized by a powerful sensation of pitching and tumbling in a different direction?
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Coriolis
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Re the "leans", what is the detection threshold?
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2-3 degrees/sec
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Peripheral vision is very important to two things discussed in this section, what are they?
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Balance and orientation
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Define autokinesis
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false movement of a static source of light
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Define oculogyral
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During a turn, an object seems to move to one side or the other
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Define oculogravic
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visual perception of tilt or pitch during acceleration
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What 3 things do fog and haze do in relation to orientation?
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alter depth perception,
obscure ground features, refract light |
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What is flicker vertigo?
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vertigo from light that is reflected in a strobe like fashion, "prop-chopping"
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What are 5 factors that can affect tolerance to disorientation?
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Alcohol
Fatigue OTC Meds Illness Hypoxia |
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What are the three types of acceleration? Define shortly
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Linear - change speed w/o changing direction
Radial - (centripetal) direction/heading change only Angular - change speed AND direction |
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What are the three "acceleration axes"?
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Gx
Gy Gz - vertical |
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What is the general tolerance to positive G's on average before symptoms appear?
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+4-5 G's
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What main physiological system is impaired during high G-loads?
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Cardiovascular
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What are three general symptoms of G-forces?
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Stagnant hypoxia - blood doesnt reach vital organs
Visual - tunnel vision, etc G-LOC - G loss of consciousness Red out - negative G's |
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What are three ways to increase one's G tolerance?
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Physical conditioning
Breathing techniques (M-1/L-1) Tech - seat design or anti-G suit |
