Sound and Hearing Flashcards
what is sound?
- sound is produced when matter is acted upon
- vibration that propagates as an acoustic wave
- sound energy
- produced in many activities (Eg. voice)
what are the two properties of sound?
amplitude (loudness) and frequency (pitch)
what is the frequency?
- measured in hertz (cycles per second)
- pitch is the frequency of waves in a given amount of time - depends of frequency
- higher pitch - higher frequency
- lower pitch - lower frequency
what is amplitude?
- sound pressure level
-magnitude of sound - loudness
-measured in decibels - 70 dBA or lower is safe hw 85 dBA or higher can damage your hearing
why is hearing useful?
helps us converse with other people, learn by listening, hear music and shows and podcasts and alert us of dangers
what are the hearing structures for the outer ear?
pinna - funnel sound energy toward ear
external auditory meatus
tympatic membrane
what are the hearing structures for the middle ear?
ossicles - 3 bones in ear
ligaments and muscles
what are the hearing structures in the inner ear?
cochlea
auditory nerve
when do we do our best hearing?
because of the shape of the ear we do our best hearing face to face - funnel and capture info and magnifies the sound
external auditory meatus - description of the structure
- small opening surrounded by cartilage (makes up the pinna)
- medial two thirds are bony
- proximal end is closed at the T.M
role of the external auditory meatus
- conducts sound energy from concha to the T.M
- role is resonator- amplify certain pitches/ freq or sound b4 reaching the tympatic membrane
tympatic membrane - description of the outer ear structure
- 8-10mm diameter with 3 layers (0.0001m thick)
- “cone of light” via otoscope - see the bottom portion will shine
- used to be labelled the eardrum - now the TM
- boundary bw outer and middle ear
tympatic membrane - function of the outer ear structure
- function is that sound energy is funneled in
- hits membrane and causes it to vibrate from sound energy
ossicles - structure within the middle ear
- smallest bone in the human body
- extends from human body extending
from T.M to oval window of cochlea - 3 ossicles in ear- malleus (hammer), incus (anvil), stapes (stirrup)
ossicles - function within the middle ear
amplify the sound energy applied to the T.M to the fluid in the cochlea
pharyngotympanic or eustachian tube - structure within the middle ear
- Aka. The auditory tube
- 3.8 cm tube running from middle ear to nasopharynx
- cartilaginous and flexible toward the nasopharynx where it is usually closed
pharyngotympanic or eustachian tube - function within the middle ear
- opens occasionally to equalise the pressure in middle ear
- also functions to drainage mucus