4 - Hearing & Speech Development Flashcards
when in gestation does the structure of the ear develop?
20 weeks gestation
at how many weeks gestation is there a functional auditory system?
25 weeks
how does the auditory system develop from 25 weeks gestation to 5-6 months?
- hair cells of cochlea, axons of auditory nerve, neurons of temporal lobe are tuned to receive signals of specific frequencies and intensities
unlike the visual system, what does the auditory system require?
- outside auditory stimulation
- speech, music, meaningful sounds from the environment
how large is the tympanic membrane?
8 x 10mm diameter
what is the organ of hearing?
the cochlea
what is the weakest quadrant of the tympanic membraen?
posterosuperior quadrant
what CN runs through the middle ear?
facial nerve (CN VII)
what are the 4 main roles of the middle ear?
- conduction
- protection
- transducer
- amplifier
why is the middle ear a conducter?
conducts sound from the outer ear to the inner ear
why is the middle ear a transducer?
- converts acoustic energy to mechanical energy
- converts mechanical energy to hydraulic energy
without middle ear function, how much acoustic energy in the air would be transmitted to inner ear fluid?
1/1000
which part of the cochlea can hear the highest frequency sound? which can hear the lowest?
highest - base
lowest - apex
why do different regions of the cochlear hear different frequencies of sounds?
the basilar membrane has different levels of stiffness at different points, so it creates a different response when fluid hits it.
which area is responsible for speech comprehension?
wernicke’s area
which are is responsible for production of speech?
broca’s area
consonants are often high/low in frequency?
high
