9.2 Human Performance And Limitations - Hearing Flashcards
what is the functions of the ear?
detect sounds through vibrations in the air
responsible for balance and sensing accelration
what are the 3 divisions of the ear?
outer ear
middle ear
inner ear
what is the purpose of the outer ear?
direct sounds down the auditory canel to the ear drum causing it to vibrate
what is the purpose of the middle ear?
beyond the eardrum, which transmits vibrations by the way of 3 bones called ossicles, to the fluid of the inner ear
what are the names of the 3 bones called in your ear?
hammer
anvil
stirrup
a muscle is also found in the middle ear, why is this?
to protect the ear from sounds over 80dB by acoustic or aural reflex
what is the limitation of acoustic and aural reflex?
cannot provide protection from sudden noises and only for up to 15 minutes
what is the middle ear filled with? whats its limitations?
air
eustachian tube can be filled with mucus as its connected to the nose and mouth
what is the inner ear filled with?
fluid
what is the last of the ossicles connected to in the inner ear?
the cochlea
how are nerve impulses transmitted to the brain?
once the cochlea detects vibration due to the motion of the fluid, they are sent via the auditory nerve
what does the amount of vibration detected mean?
the amount detected depends on the volume and pitch of the sound
what is the frequency range that a young person can hear?
20 and 20000 cycles per second (Htz)
what impact can negative effects have on performance? (5)
-can be annoying (sudden sounds or constant loud sounds)
-interfere with verbal comms
-cause accident by masking warning signals
-be fatiguing and affect concentration and decision making
-damage workers hearing
what sort of noise is generally more disruptive?
intermittent and sudden noises
what is the regulation covering hearing at work?
control of noise at work regulation 2005
what is the aim of the control of noise at work regulation 2005?
to ensure workers hearing is protected from excessive noise at their place of work which could cause them to lose their hearing or suffer from tinnitus
at what level must employers provide hearing protection?
85dBs
at what level must employers assess the risk to workers health and provide with information and training?
80 dBs
what is the exposure limit?
87dBs when wearing hearing protection
what is noise dose?
exposure to any sound over 80dB and measured over an 8 hour day time-weighted average
what is the maximum TWA?
90 dB
what could occur if the TWA were to exceed 85dB for 8 hours?
hazardous and lead to damaging the inner ear
what can hearing protection interfere with?
verbal communications
what is hearing loss known as?
noise induced hearing loss (NIHL)
what causes NIHL?
the hair-like cells on the basilar membrane being damaged beyond repair
why is it difficult to notice hearing loss?
as it occurs gradually and by the time you notice, you are too late
what is the term for when hearing deteriorates with age?
presbycusis
