Hearing and Balance Flashcards
Consists of the auricle and the external acoustic meatus.
External Ear
The shell-shaped projection surrounding the opening of the external acoustic meatus. Composed of elastic cartilage covered with thin skin.
Auricle
The thicker, fleshy area of the ear.
Helix
The earlobe. Lacks supporting cartilage.
Lobule
The auditory canal. A short, curved tube that extends from the auricle to the eardrum.
External Acoustic Meatus
Modified apocrine sweat glands that secrete cerumen.
Ceruminous Glands
Earwax. A yellow-brown waxy fluid.
Cerumen
The eardrum. A thin, translucent, connective tissue membrane that vibrates due to sound waves.
Tympanic Membrane
A small, air-filled, mucosa-lined cavity in the petrous part of the temporal bone.
Middle Ear
Superior opening in the bony wall of the ear.
Oval Window
Inferior opening in the bony wall of the ear.
Round Window
Runs obliquely downward to link the middle ear cavity with the nasopharynx. Opens to equalize pressure int eh middle ear cavity with external air pressure.
Pharyngotympanic Tube (Eustachian Tube)
The three smallest bones in the body. Span the tympanic cavity. Transmit the vibratory motion of the eardrum to the oval window.
Auditory Ossicles
The “hammer.”
Malleus
The “anvil.”
Incus
The “stirrup.”
Stapes
Skeletal muscle that inserts on the malleus. Helps limited the ossicle’s vibration.
Tensor Tympani
Skeletal muscle that inserts on the stapes. Helps limited the ossicle’s vibration.
Stapedius
Site of all the receptor machinery.
Inner Ear
System of channels worming through the bone.
Bony Labyrinth
A continuous series of membranous sacs and ducts contained withing the bony labyrinth.
Membranous Labyrinth
A fluid that is continuous with CSF. Suspends the membranous labyrinth.
Perilymph
Fluid in the interior of the membranous labyrinth.
Endolymph
The central egg-shaped cavity of the bony labyrinth.
Vestibule
Sac that is continuous with the membranous labyrinth extending anteriorly into the cochlea.
Saccule
Sac that is continuous with the semicircular ducts extending into the semicircular canals posteriorly.
Utricle
Project from the posterior aspect of the vestibule. Each one is oriented in one of the three planes of space. The anterior and posterior ones are oriented at right angles to each other in the vertical plane; the lateral one lies horizontally.
Semicircular Canals
Snakes through each semicircular canal. Communicates with the utricle.
Semicircular Duct
Large swelling of the semicircular duct. Houses an equilibrium receptor region that respond to rotational movements of the head.
Ampulla
A spiral, conical, bony chamber. Houses the auditory receptors.
Cochlea
Bony pilar that the cochlea coils around.
Modiolus
Runs through the center of the cochlea.
Cochlear Duct
The receptor organ of hearing.
Spiral Organ
A thin shelflike extension of bone that spirals up the modiolus. With the cochlear duct, divides the cavity of the bony cochlea into three chambers.
Osseous Spiral Lamina
Three chambers of the cochlea.
Scalae
Continuous with the vestibule, begins that the oval window. Contains perilymph
Scala Vestibuli
The cochlear duct. Contains endolymph
Scala media
Terminates at the round window. Contains perilymph.
Scala tympani
Plays a role in sound reception.
Basilar Membrane
Hearing receptor cell.
Inner Hair Cells
Hearing receptor cell.
Outer Hair Cells
A division of the vestibulocochlear nerve. Fibers coil around the bases of the hair cells and run from the spiral organ through the modiolus to the brain.
Cochlear Nerve
The pressure disturbance produced by a vibrating object and propagated by the molecules of the medium.
Sound
The number of waves that pass a given point in a given time.
Frequency
How we perceive different sound frequencies.
Pitch
Provides the richness and complexity of sounds that we hear.
Quality
The height of the sine wave, reveals a sounds intensity.
Amplitude
Our subjective interpretation of sound intensity
Loudness
Logarithmic unit of sound intensity
Decibels
Soundwave strike this, setting it vibrating at the same frequency.
Tympanic membrane
The motion of the tympanic membrane is amplified and transferred to the oval window by these.
Auditory ossicles
The vibration of the oval window sets the perilymph in this chamber in motion.
Scala vestibuli
Sounds with frequencies high enough to ear are transmitted through the cochlear duct to the perilymph of the scala tympani, vibrating hair cells on this. Like strings of a harp, shorter hair cells sensitive to higher frequencies are on one end while longer hair cells sensitive to lower frequencies are at the other.
Basilar Membrane
Location where auditory bipolar cell bodies reside.
Spiral ganglion
Where action potentials from the spiral ganglion and cochlear nerve reach the medulla.
Cochlear nuclei
Where neurons from the medulla project in the auditory pathway.
Superior olivary nucleus
The auditory reflex center in the midbrain
Inferior colliculus
Provides conscious awareness of sound
Primary auditory cortex
Occurs when something hampers sound conduction to the fluids of the internal ear.
Conduction deafness
Results from damage to neural structures at any point from the cochlear hair cells to and including the auditory cortical cells.
Sensorineural deafness
A ringing, buzzing, or clicking sound in the ears in the absence of auditory stimuli
Tinnitus
A labyrinth disorder that affects all three parts of the internal ear.
Meniere’s Syndrome
Consists of the semicircular canals, the vestibule, and the receptors they contain.
Vestibular apparatus
Sensory receptor organs that monitor the position of the head in space.
Maculae
Vestibule receptor cells that are embedded in the otolith membrane.
Hair cells
A true cilium of vestibular hair cells.
Kinocilium
A jellylike mass studded with tiny calcium carbonate stones.
Otolithic membrane
Calcium carbonate stones in the otolithic membrane. Increase the membrane’s weight and inertia.
Otoliths
The receptor for rotational acceleration
Crista Ampularis
