lOMoAR cPSD| 22896205
APEA STUDY GUIDE EXAM 1 PHARMACOLOGY, PHYSICAL
ASSESSMENT & PATHOPHYSIOLOGY CHAMBERLAIN
UNIVERSITY WEEK 2 H EENT: EAR
• Located within temporal bone of skull &
on each side of face
• Ear complex organ responsible for
hearing & balance
• External, middle, & inner ear structures
conduct sound waves through ear and to
brain via nerves o External ear
Pinna: visible flap on the side of the head
External auditory meatus aka ear canal
• Canal passes through temporal bone to tympanic membrane (ear drum) o Tympanic
membrane separates external & middle ear
External ear made up of auricle (the cartilaginous outer structure) &
external acoustic meatus (canal)
• Canal lined with tiny hair follicles (cilia) & ear wax to keep foreign particles out of the
ear
o Middle ear
Tympanic cavity: hollow area in the bone contains 3 tiny bones
(malleus, incus, and stapes) making up ossicles
• Malleus adjacent to tympanic membrane
• Stapes fits against the oval window, a membrane connecting the
middle ear and the inner ear
Middle ear cavity opens into auditory or eustachian tube, which
connects to the nasopharynx This tube equalizes pressure in the
middle ear with pressure in the external ear canal o Equalization
important if atmospheric pressure changes suddenly, as when an
airplane takes off
pg. 1
, lOMoAR cPSD| 22896205
Chewing or swallowing helps to equalize the pressure on either side
of the tympanic membrane.
Middle ear cavity continuous with the mastoid air cells in the mastoid
process of the temporal bone around the ear.
• Continuous mucous membrane lines middle ear cavity, mastoid
cells, the auditory tube, & respiratory tract o Significant because it
provides a path for direct spread of infection through these
structures
Sound travels through the canal to the tympanic membrane (eardrum),
the outermost portion of the middle ear
• Small ossicles (bones) called malleus, incus, and stapes make up
the inner portion of the middle ear o Ossicles transmit sound
vibrations from the eardrum to the inner ear.
o Inner ear - aka labyrinth
Consists of cochlea and semicircular canals, jointed by a vestibule
(Organ of Corti & semicircular canals)
• Semicircular canals of inner ear responsible for balance &
equilibrium
Structures consist of a bony labyrinth filled with a fluid, perilymph,
inside of which is a membranous labyrinth filled with endolymph
• Cochlea contains a complex arrangement of membranes
surrounding the organ of Corti, where specialized hair cells (nerve
receptors) provide stimuli to the sensory neurons for hearing o
These neurons form the cochlear branch of the auditory nerve
(cranial nerve VIII), which conducts impulses to the temporal
lobe for reception and interpretation of sound
o Some fibers from each ear cross to the auditory cortex in the opposite
hemisphere, and some fibers remain on the same side, meaning that each
auditory area receives some sound from each ear.
Inner ear made up of a spiral structure that responds to sound waves called
the cochlea and three curved semicircular canals
pg. 2
, lOMoAR cPSD| 22896205
• Cochlea translates sound vibrations received from the middle ear
into auditory signals, which are transmitted to the brain via the
vestibulocochlear nerve.
• In addition to hearing, the inner ear is also responsible for balance.
Hearing loss
• 2 types: conduction deafness & sensorineural deafness (sometimes
sensorineural is broken down into sensory and neural deafness).
Tests comparing conduction by air through the external canal and
conduction through the mastoid bone can assist in differentiating
the type of deafness.
o Conduction deafness:
Sound is blocked in
the external ear or
middle ear
Examples:
• Accumulation of wax or foreign object in external ear canal can
block sound waves
• Scar tissue or adhesions may impair the function of the tympanic
membrane or ossicles
Conductive hearing loss occurs when auditory stimuli
are not adequately transmitted through the auditory
canal, tympanic membrane, middle ear, or ossicle chain
to the inner ear
• Can be a temporary loss from impacted cerumen
Conductive hearing loss – signs and symptoms o
Sensorineural impairment develops with damage to the
organ of Corti or the auditory nerve. Damage can
result from:
• Infection particularly viral infections:
o Rubella o Influenza o
Herpes
• Head trauma
pg. 3
, lOMoAR cPSD| 22896205
• Neurologic disorders affecting the auditory nerve or temporal lobe
Sensorineural hearing loss is loss of hearing r/t damage of the end organ
for hearing/ cranial nerve VIII
Sensorineural hearing loss occurs with disorders that affect the inner ear,
auditory nerve, or auditory pathways to the brain
• Numerous drugs have ototoxic potential, a consequence of which
is sensorineural hearing loss Sensorineural hearing loss – signs
and symptoms
• Ototoxic o Ototoxic drugs can cause temporary/permanent hearing
loss Antibiotics
• Streptomycin
• Neomycin
• Vancomycin
Analgesics
Aspirin
o Tinnitus & hearing loss
Ibuprofen
Diuretic: furosemide (Lasix)
Some antineoplastic o Early signs of Ototoxicity
Early sign of toxicity tinnitus, ringing or buzzing in ears
Management of tinnitus
• Noise suppression therapy
• Medications that help reduce severity of the condition o Forms of
alternative medicines: Lipo-flavonoids
• No cure for condition, just therapies to reduce the symptoms
• Most common cause of conductive hearing loss in the elderly
• Presbycusis is the sensorineural loss o Occurs in elderly people
owing to a reduced number of hair cells or receptor cells or other
degeneration in the cochlea
• Congenital deafness o May be inherited or result from infection or
trauma during pregnancy or delivery o early dx and tx are essential
for development of child
pg. 4
APEA STUDY GUIDE EXAM 1 PHARMACOLOGY, PHYSICAL
ASSESSMENT & PATHOPHYSIOLOGY CHAMBERLAIN
UNIVERSITY WEEK 2 H EENT: EAR
• Located within temporal bone of skull &
on each side of face
• Ear complex organ responsible for
hearing & balance
• External, middle, & inner ear structures
conduct sound waves through ear and to
brain via nerves o External ear
Pinna: visible flap on the side of the head
External auditory meatus aka ear canal
• Canal passes through temporal bone to tympanic membrane (ear drum) o Tympanic
membrane separates external & middle ear
External ear made up of auricle (the cartilaginous outer structure) &
external acoustic meatus (canal)
• Canal lined with tiny hair follicles (cilia) & ear wax to keep foreign particles out of the
ear
o Middle ear
Tympanic cavity: hollow area in the bone contains 3 tiny bones
(malleus, incus, and stapes) making up ossicles
• Malleus adjacent to tympanic membrane
• Stapes fits against the oval window, a membrane connecting the
middle ear and the inner ear
Middle ear cavity opens into auditory or eustachian tube, which
connects to the nasopharynx This tube equalizes pressure in the
middle ear with pressure in the external ear canal o Equalization
important if atmospheric pressure changes suddenly, as when an
airplane takes off
pg. 1
, lOMoAR cPSD| 22896205
Chewing or swallowing helps to equalize the pressure on either side
of the tympanic membrane.
Middle ear cavity continuous with the mastoid air cells in the mastoid
process of the temporal bone around the ear.
• Continuous mucous membrane lines middle ear cavity, mastoid
cells, the auditory tube, & respiratory tract o Significant because it
provides a path for direct spread of infection through these
structures
Sound travels through the canal to the tympanic membrane (eardrum),
the outermost portion of the middle ear
• Small ossicles (bones) called malleus, incus, and stapes make up
the inner portion of the middle ear o Ossicles transmit sound
vibrations from the eardrum to the inner ear.
o Inner ear - aka labyrinth
Consists of cochlea and semicircular canals, jointed by a vestibule
(Organ of Corti & semicircular canals)
• Semicircular canals of inner ear responsible for balance &
equilibrium
Structures consist of a bony labyrinth filled with a fluid, perilymph,
inside of which is a membranous labyrinth filled with endolymph
• Cochlea contains a complex arrangement of membranes
surrounding the organ of Corti, where specialized hair cells (nerve
receptors) provide stimuli to the sensory neurons for hearing o
These neurons form the cochlear branch of the auditory nerve
(cranial nerve VIII), which conducts impulses to the temporal
lobe for reception and interpretation of sound
o Some fibers from each ear cross to the auditory cortex in the opposite
hemisphere, and some fibers remain on the same side, meaning that each
auditory area receives some sound from each ear.
Inner ear made up of a spiral structure that responds to sound waves called
the cochlea and three curved semicircular canals
pg. 2
, lOMoAR cPSD| 22896205
• Cochlea translates sound vibrations received from the middle ear
into auditory signals, which are transmitted to the brain via the
vestibulocochlear nerve.
• In addition to hearing, the inner ear is also responsible for balance.
Hearing loss
• 2 types: conduction deafness & sensorineural deafness (sometimes
sensorineural is broken down into sensory and neural deafness).
Tests comparing conduction by air through the external canal and
conduction through the mastoid bone can assist in differentiating
the type of deafness.
o Conduction deafness:
Sound is blocked in
the external ear or
middle ear
Examples:
• Accumulation of wax or foreign object in external ear canal can
block sound waves
• Scar tissue or adhesions may impair the function of the tympanic
membrane or ossicles
Conductive hearing loss occurs when auditory stimuli
are not adequately transmitted through the auditory
canal, tympanic membrane, middle ear, or ossicle chain
to the inner ear
• Can be a temporary loss from impacted cerumen
Conductive hearing loss – signs and symptoms o
Sensorineural impairment develops with damage to the
organ of Corti or the auditory nerve. Damage can
result from:
• Infection particularly viral infections:
o Rubella o Influenza o
Herpes
• Head trauma
pg. 3
, lOMoAR cPSD| 22896205
• Neurologic disorders affecting the auditory nerve or temporal lobe
Sensorineural hearing loss is loss of hearing r/t damage of the end organ
for hearing/ cranial nerve VIII
Sensorineural hearing loss occurs with disorders that affect the inner ear,
auditory nerve, or auditory pathways to the brain
• Numerous drugs have ototoxic potential, a consequence of which
is sensorineural hearing loss Sensorineural hearing loss – signs
and symptoms
• Ototoxic o Ototoxic drugs can cause temporary/permanent hearing
loss Antibiotics
• Streptomycin
• Neomycin
• Vancomycin
Analgesics
Aspirin
o Tinnitus & hearing loss
Ibuprofen
Diuretic: furosemide (Lasix)
Some antineoplastic o Early signs of Ototoxicity
Early sign of toxicity tinnitus, ringing or buzzing in ears
Management of tinnitus
• Noise suppression therapy
• Medications that help reduce severity of the condition o Forms of
alternative medicines: Lipo-flavonoids
• No cure for condition, just therapies to reduce the symptoms
• Most common cause of conductive hearing loss in the elderly
• Presbycusis is the sensorineural loss o Occurs in elderly people
owing to a reduced number of hair cells or receptor cells or other
degeneration in the cochlea
• Congenital deafness o May be inherited or result from infection or
trauma during pregnancy or delivery o early dx and tx are essential
for development of child
pg. 4
