Lecture 15 - Human Factors 3 Flashcards
_______ = sound pressure perceived as loudness.
amplitude
_______ = cycles per second perceived as pitch.
frequency
What is the eardrum also known as?
Tympanic membrane
An ________ ______ runs from the beginning to the end of the cochlea, splitting it into an upper and lower part. This is called the ?
elastic partition; basilar membrane
Bending cause channels, which are on the tips of the _____ to open up.
stereocilia
High frequencies cause vibrations at the _______ of the cochlea, and low frequency vibrations cause vibrations at the _______.
base;apex
Sound intensity is also known as ______ intensity, and it is defined as the _____ power per unit area.
acoustic; sound
What is the SI unit of sound intensity?
W/m2
It is common to express the sound intensity using a logarithmic scale known as the _________ scale.
decibel
The dB is a ________ way of describing a ratio.
logarithmic
The dB scale and the intensity values are _______ measures of sound.
objective
Sound with equal intensities but different _______ are perceived by the same person to have unequal loudness.
frequencies
A 60dB sound with a frequency of 1000Hz sounds (louder/softer) than a 60dB sound with a frequency of 500Hz.
louder
A ______ is used to indicate an individuals perception of loudness.
phon
______ and ______ are used to indicate an individual perception of loudness.
phons; sones
What does sones tell us that phons don’t?
how much louder one sound is than another
Psychophysical scale of sound is an interaction between what two things?
Amplitude and frequency
What is the range we’re most sensitive to tones between?
1000-4000Hz
Hearing threshold elevation at high frequencies is known as?
Presbycusis
What does the audible spectrum decrease to with age?
50-8000Hz
Noice-induced hearing loss is caused by damage to what?
structures in inner ear
What is one of the most common work-related illnesses in the US?
NIHL
Long or repeated exposure to sounds at or above ____ dB can cause hearing loss.
85
What is most NIHL caused by?
Damage and eventual death of hair cells
Human hair cells don’t grow back (T/F)/
True
NIOSH recommends that every increase by 3dBA ______ the amount of noise and _______ the recommended exposure time.
doubles; halves
Whats the most common construction trade to have NIHL?
Welders (79.5%)
_______ has been isolated as one of the highest problematic areas for NIHL in Canada.
Carpentry
The average ___ year old carpenter has the ears of a ___ year old person who has not been exposed to noise.
25;50
Loud noise exposure can also cause ______; a ringing, buzzing or roaring in the head when no external noise is present.
tinnitus
Tinnitus can be caused by damage to improper transmission through sensory _______ or pathway to the ______.
organs; brain
Sometimes exposure to impulse or continuous loud noise causes a temporary hearing loss that disappears ____ to ____ hours later. What is this called?
16;48; temporary threshold shift or auditory fatigue
In intense noise, displacement of basilar membrane of maximum vibration is large, and hair cells are ______ by considerable force.
bent
Overstimulation leads to temporary ________ or hair cells.
paralysis
Temporary threshold shift (TTS) is usually measured ___ minutes following exposure to avoid recovery.
2
TTS usually experienced at frequencies high than the exposure frequency, usually ______Hz.
4000
________ noise causes raised levels of cortisol and other stress hormones.
chronic
There is a _____ correlation between long term noise exposure above 67-70 dB and hypertension.
weak
Noise levels of _____ dB(A) at night may increase the risk of myocardial infarction.
50
The vestibular system encodes _______ and _______ acceleration of the head.
linear; rotary
The vestibular system senses constant _______ acceleration by earth gravity and thus signals to the brain head movement and position with respect to constant gravitational _______.
linear; acceleration
What three things does the vestibular system do?
- Detect acceleration forces
- Maintains upright posture/balance
- Controls eye position relative to head
_______ _______ detect angular acceleration in 3 axes.
semicircular canals
In semicircular canals, a ____ is embedded in jelly-like material (cupola) is supported by hair cells that bend and fire in response to head rotation.
crista
_________ ____ detect linear acceleration.
Vestibular sacs
The vestibular sacs (utricle and saccule) are hair cells in jelly like substance that ____ behind when the head moves.
lag
________ refers to involuntary movement of the eyes.
Nystagmus
What may nystagmus sometimes be accompanied with?
Vertigo
Individuals exposed to intense noice may have evidence of vestibular pathology only when there is an _________ hearing loss.
asymmetrical
What are the two types of nystagmus?
- Spontaneous
2. Positional
