Lecture #3b - anatomy of hearing Flashcards
define hearing :
sense through which spoken language or non-speech sounds are received, transmitted and processed by the auditory system
how many components does the auditory system has?
2
what are the two components of the auditory system ?
peripheral auditory system & central auditory system
where anatomically is considered the peripheral auditory system ?
outer ear to auditory nerve
where anatomically is considered the central auditory system ?
beyond auditory nerve to cerebral cortex
what are the parts of the peripheral auditory system ?
- outer ear
- middle ear
- inner ear “cochlea”
- auditory nerve
what are the two key components of the outer ear ?
pinna (auricle) and external ear canal
what term is used to describe the “visible cartilaginous portion” ?
pinna
TRUE OR FALSE
the pinna varies in size and shape ?
TRUE (everyone can have different ear sizes)
what are some functions of the pinna ?
- protects middle ear from damage
- helps eliminate front-back confusion
- collects sounds
- enhances sound pressure of high frequency sounds
what is the MAIN function ofthe pinna ?
to protect from foreign substances
when the pinna collects sound what do they do with it ?
they move it in and towards the middle ear
what is the part of the ear that we usually pierce called ?
lobule
what part of the ear has the largest blood supply and can helps to distribute warmth and balance ?
lobule
where is the “helix” on the ear ?
the outer rim of the ear
what is the tragus ?
- a small piece of cartilage
- role to ditect sounds inwards and detect where sounds are coming from
what is the lobule’s major function ?
to supply blood and maintain warmth and balance
what is another term for the external ear canal ?
external auditory meatus
what is the external ear canal ?
tunnel between pinna and the eardrum
the external ear canal is a tunnel between what two parts ?
the pinna and the eardrum
what is the external ear canal made out of when near the pinna ?
cartilaginous
what is the external ear canal made out of when near the eardrum ?
bony
in the average adult, how long is the external ear canal tunnel ?
around 2.5 cm
what direction is the external ear canal angled towards in adults ?
angled downwards
what direction is the external ear canal angled towards in children ?
horizontally
why are children more prone to ear infections ?
adults’ ear canal is angled downwards which makes it harder for foreigh substances to get in whereas children’s are angled horizontalloy therefore easier to get infected
what are the external ear canal functions ?
- protects eardrum from trauma
- produces cerumen to keep skin moist and trap debris
- enhances sound pressure of mid/high frequency
what is cerumen ?
earwax
what is mid/high-frequency ?
2500-3500 Hz sounds by around 15 db SPL
what shape does the eardrum have ?
”s” shape
what are the key components of the middle ear ?
- middle ear cavity
- tympanic membrane (eardrum)
- ossicles
- eustacian tube
what is the more common term used for tympanic membrane ?
eardrum
where is the auditory nerve located in the ear?
all the way at the back
where is the middle ear cavity located between ?
external auditory meatus and cochlea
are there bones in the middle ear ?
yes
what is the bone in the middle ear covered by ?
thing mucous membrane
FILL IN THE BLANK
the middle ear is a hollow space between ____________
temporal bone (less than around 2cc in volume)
TRUE OR FALSE
ideally the middle ear cavity is filled with air
TRUE
but not fully fluid
what does it mean if our middle ear cavity is not filled with air ?
you probably have an ear infection
where can we find the tympanic membrane ?
right at the end of the ear canal
what is the tympanic membrane stretched across ?
stretched across opening of external ear canal (concave boundary between outer and middle ears
what is the size of the tumpanic membrane ?
very thin (0.07mm)
what term is defined as “flexible and strong”
tympanic membrane (eardrum)
what part of the ear creates the signal ?
middle creates signal
what does the tympanic membrane move in response to ?
sound presssure
how many layers of the tympanic membrane ?
3
what are the 3 layers of the tympanic membrane ?
- skin
- fibrouss connective tissue
- mucous membrane
where is the malleus embedded ?
in the middle ear (tympanic membrane)
FILL IN THE BLANK
the malleus is embedde in the middle ear to support __________
transmission of sound
what is the primary function of the outer ear?
a) to amplify sound
b) to convert sound waves into electrical signal
c) to collect and direct sound waves into the ear canal
d) to house the sensory cells for balance
c) to collect and direct sound waves into the ear canal
what is the visible part of the outer ear called ?
a) cochlea
b) auricle (pinna)
c) tympanic membrane
d) eustrachian tube
b) auricle (pinna)
the external auditory canal (external acoustuc meatus) extends from the :
a) auricle to the cochlea
b) auricle to the tympanic membrane
c) tympanic membrane to the cochlea
d) cochlea to the brain
b) auricle to the tympanic membrane
what is the primary role of the cerumen (earwax) produced in the outer ear ?
a) to protect and lubricate the ear canal
b) to amplify sound
c) to detect sound frequency
d) to transmit sound waves to the cochlea
a) to protect and lubricate the ear canal
the outer ear is primarily involved in which aspect of hearing ?
a) sound amplification
b) sound frequency discrimination
c) sound signal transduction
d) sound localization and collection
d) sound localization and collection
what is the primary function of teh tympanic membrane ?
a) to transmit sound waves to the cochlea
b) to covert sound waves into electrical signals
c) to vibrate in response to sound waves and transmit vibrations to the middle ear
d) to prtect the inner ear from damage
c) to vibrate in response to sound waves and transmit vibrations to the middle ear
the tympanic membrane is made up of how many layers ?
a) one
b) two
c) three
d) four
c) three
