sound -...
TRANSCRIPT
Sound
By: Avril Marshall, Gabi Luna, Juan Luna, and Alexya Avila
Anatomy of SoundOrgans that aid in hearing:
-Eardrum: Slender membrane, vibrates when sound waves are received; transmits waves to ossicles
-Eustachian Tube: connects inner ear to nasopharynx(upper
part of pharynx connecting nasal cavity); equalizes air pressure on both sides of eardrum
-Vestibule: where the 3 semicircular canals open, it is responsible for equilibrium
Cochlea: Bony structure for hearing; transforms vibrations into nervous impulses
Lateral semicircular canal: horizontal canal, monitors head movement, makes sure equilibrium is maintained
-Cochlear nerve: nerve that transmits auditory messages
in the cochlea to brain, joins with vestibular nerve to form
auditory nerve
Anatomy of SoundOrgans that aid in hearing:
-Vestibular Nerve:nerve transmits messages related to
equilibrium to the brain, emanates from vestibule and the
semicircular canals
-Superior semicircular canal: vertical canal, perpendicular
to temporal bone; monitors head movements for
equilibrium.
-Auditory Ossicles: smallest bones in human body, amplify
the vibrations of the eardrums
-Posterior semicircular canal: Vertical canal parallel to
Temporal bone; monitors head movements to make sure
equilibrium is maintained
-Pinna: Soft cartilage part of ear located at side of head;
allows sound to be collected
-Acoustic Meatus: Canal carrying sounds collected by the Pinna to eardrum, covered with cerumen, a waxy substance that keeps dust out
-Internal Ear: Liquid filled cavity hollowed out by temporal bone that transforms sound vibrations into nerve influxes to be interpreted by brain
-Middle Ear:Air-filled cavity hollowed out of the temporal bone; it receives sounds from the external ear, amplifies them through the auricles and transmits them to the internal ear.
-External Ear:Visible portion of the ear enabling sounds to be collected and directed to the middle ear through the acoustic meatus.
Parts of the Brain that aid in sound
Thalamus: processing for motor response
Midbrain: where sound is fully integrated
Physiology of Sound
Outer Ear
An external sound from the environment is received in wave form by the outer ear. The first structure of the ear that the sound wave hits would be the Pinna which directs the wave towards the ear canal.
The ear canal then makes the sound louder while directing the sound waves towards the tympanic membrane.
Physiology of Sound Con’td
Middle Ear
When the sound waves reach the Tympanic membrane it causes the membrane to create vibrations that transfer the sound energy to the Ossicular chain.
In the ossicular chain the sound signal is amplified about 25 decibels as it transfers closer to the inner ear.
The transmission of sound is most optimal when the air pressure in the ear is equalized between the outer and middle ear.
Physiology of Sound Con’td
Physiology of Sound Con’td
Inner ear
After the sound waves enter the inner ear through the ear oval window it reaches the Cochlea which has 3 fluid-filled chambers essential to the protection of the Basilar membrane and the Organ of corti.
The Organ of Corti has approximately 30,000 cilia, otherwise known as hair cells, in
rows that are individually connected to nerve fibers that send impulses to the cochelar branch of the VIIIth cranial nerve.
Physiology of Sound Con’td
Physiology of Sound Con’td
Nerves
The nerve impulses from the sound wave then travel from the VIIIth cranial nerve to the brainstem where the basic breakdown of the sound is performed.
Then the nerve impulse travels toward the Thalamus which prepares the motor response for the sound.
Lastly, the signal is transported to the temporal lobes/ Auditory cortex.
Physiology of Sound Con’td
Homeostatic Imbalances
Myringitis● What is it
○ This is a painful problem caused by inflammation of the middle ear as well as
oozing blisters on the eardrum.
● Symptoms○ Drainage from the ear
○ Hearing impairment
○ Sudden onset of ear pain that lasts 1 to 2
days
○ Fever
● Treatment○ Antibiotics
■ Ear drops which offer local
anesthesia
○ Rupturing any vesicles on the eardrum
● Causes○ Myringitis is usually caused by an infection with
a virus or bacteria○ Bacteria is called
■ Mycoplasma pneumoniae
■ Streptococcus pneumoniae
■ Staphylococcus aureus
○ Often begins in the eardrum\
● Common○ children 6 mo. - 5 yrs.
Otosclerosis● What is it
○ Otosclerosis is an abnormal bone growth in the middle ear that causes hearing
loss.■ People who have otosclerosis
have an abnormal sponge-like
bone growing in the middle ear.
This growth prevents the ear
bones from vibrating in response
to sound waves.
● Causes○ The cause of otosclerosis is unknown.
● Symptoms○ Hearing loss (slow at first, but gets worse over
time)○ Ringing in the ears (tinnitus)○ Vertigo or dizziness
● Treatments○ Otosclerosis may slowly get worse. The
condition may not need to be treated until you have significant hearing problems
○ Medication○ Hearing Aid○ Surgery
● Possible Complications○ Complete deafness○ Funny taste in the mouth○ Infection, dizziness, pain, or a blood clot in the
ear after surgery○ Nerve damage
Severe Hearing loss● What is it
○ You can hear some sound but very poorly ○ Only able to hear very loud sounds or not able
to hear anything.
● Cause○ lifetime exposure to noise and other damaging
factors slowly wear down the ears' delicate mechanics.
○ Medications○ Illnesses○ Faulty gene ( babies)○ Infections with women that are pregnant
● Levels ○ Conductive hearing loss○ Sensorineural hearing loss○ Mixed hearing loss
● Prevention○ Avoid too much noise○ Wear hearing protection
○ Limit loud sounds ○ Remove Earwax Properly ○ Check medications for hearing risks
● Treatments○ Surgery may reverse hearing○ Antibiotics○ Hearing aid
● Statistical Facts○ 1 out of 3 people age 65-74 has some level
of hearing loss○ 75 and up it becomes 1 out of every two
people○ Third most common health problem in the
U.S○ 20% of babies born with it also have another
genetic condition
Meniere disease ● What is it
○ Meniere’s disease is a disorder that affects the inner ear. This disorder causes vertigo (a
sensation of spinning), hearing problems, and a ringing sound in the ear.
● Causes○ The cause of Meniere’s disease isn’t known, but
scientists believe it’s caused by changes in the fluid in tubes of the inner ear.
● Tests○ Audiometry○ Electronystagmography○ MRI○ CT
● Symptoms○ Come as “episodes” or “attacks”
■ vertigo (attacks can last anywhere from a few minutes to 24 hours)
■ loss of hearing in the affected ear■ tinnitus (a sensation of ringing) in the
affected ear■ a feeling of fullness in the affected ear■ loss of balance■ headaches■ nausea, vomiting, and sweating caused
by severe vertigo
● Treatments○ Medication○ Rehab and hearing aids○ Surgery○ Changing your diet may help to reduce the
amount of fluid in the inner ear and ease symptoms
Fun Facts● The number one cause of hearing loss is exposure to excessively loud sounds
(85 decibels or higher).● You do not need to clean wax out of your ears unless you have an abnormal
condition. Ears push excess wax out as needed.● Your ears never stop hearing, even when you sleep. Your brain just ignores
incoming sounds.● Not all living creatures hear with ears. Fish respond to pressure changes, and
male mosquitoes use antennae.
Essential vocabulary● Decibels: unit used to measure sound
● Pinna: The pinna is a concave cartilaginous structure, which collects and directs sound waves traveling in air into the ear canal or external auditory meatus.
● Eustachian tube (usta-tion): connects inner ear to nasopharynx
● Vestibule (vest- ibule): where the 3 semicircular canals open
● Auditory ossicles: amplify the vibrations of the eardrums
● Meniere´s disease: a disorder that affects the inner ear
Sources● http://beautiful-sound.mpacula.com/graphics/super8.png
● http://visual.merriam-webster.com/human-being/sense-organs/hearing/structure-ear.php
● http://www.webmd.com/a-to-z-guides/hearing-loss-causes-symptoms-treatment#1
● http://www.healthline.com/health/menieres-disease#LifestyleTreatments4
● https://medlineplus.gov/ency/article/001036.htm
● http://emedicine.medscape.com/article/858558-treatment
● http://www.workplaceintegra.com/hearing-articles/Ear-anatomy.html
● http://www.brainfacts.org/Sensing-Thinking-Behaving/Senses-and-Perception/Articles/2012/Hearin
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● https://www.bigstockphoto.com/image-28560236/stock-vector-vector-human-brain-diagram-side-vi
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