Hearing and Equilibrium Flashcards
What are the three parts of the ear?
External ear, Middle ear, Inner ear
What is the function of the Auricle (Pinna)?
Collects sound waves and directs them into the external acoustic meatus.
What is the function of the External Acoustic Meatus?
Channels sound waves to the tympanic membrane.
What is the function of the Tympanic Membrane (Eardrum)?
Vibrates in response to sound waves, transmitting them to the middle ear.
What are the structures of the middle ear?
Auditory Ossicles (Malleus, Incus, Stapes), Oval Window
What is the function of the Auditory Ossicles?
Transmit and amplify vibrations from the tympanic membrane to the inner ear.
What is the function of the Oval Window?
Transmits vibrations from the stapes to the fluid in the inner ear.
What happens in the middle ear?
Sound vibrations are transmitted from the tympanic membrane through the ossicles to the oval window, amplifying the sound.
Where is the Eustachian tube located?
It connects the middle ear to the pharynx (throat).
What is the role of the Eustachian tube?
Equalizes air pressure on both sides of the tympanic membrane to maintain proper hearing and prevent damage.
What are the structures of the inner ear?
Labyrinths, Semicircular Canals, Cochlea, Scala Vestibuli & Scala Tympani, Round Window, Cochlear Duct, Vestibular Membrane & Basilar Membrane, Spiral Organ (Organ of Corti), Hair Cells, Tectorial Membrane
What is the function of the Cochlea?
Contains the spiral organ responsible for hearing.
What is the function of the Spiral Organ (Organ of Corti)?
Contains hair cells that detect sound vibrations.
True or False? The spiral organ (organ of Corti) has the hearing receptors.
True
What are the hearing receptors?
Hair cells
They are mechanoreceptors.
What are the steps in the creation of sensory impulses from the ear?
- Sound waves enter the external auditory canal. 2. The tympanic membrane vibrates. 3. The auditory ossicles amplify vibrations. 4. The stapes transmits vibrations to the oval window. 5. Vibrations move through the fluid of the cochlea. 6. Hair cells in the organ of Corti detect sound and send impulses.
Which cranial nerve is involved in hearing?
The vestibulocochlear nerve (cranial nerve VIII).
Where in the brain is the auditory cortex located?
In the temporal lobe of the cerebrum.
What frequency range can a young person with normal hearing detect?
20 Hz to 20,000 Hz
What do decibels (dB) measure?
Sound intensity (loudness).
What scale are decibels measured on?
A logarithmic scale.
How much more intense is a sound of 20 dB compared to 10 dB?
10 times more intense.
How much more intense is a sound of 30 dB compared to 10 dB?
100 times more intense.
What branch of what cranial nerve triggers action potentials to the brain?
The cochlear branch of the vestibulocochlear nerve (cranial nerve VIII).
What determines the loudness of a sound?
The amplitude of sound waves (greater amplitude = louder sound).
What determines the pitch of a sound?
The frequency of sound waves (higher frequency = higher pitch).
What is conductive hearing loss?
Caused by problems in the outer or middle ear, preventing sound from reaching the inner ear (e.g., earwax blockage, damage to ossicles).
What is sensorineural hearing loss?
Caused by damage to the inner ear (cochlea) or auditory nerve (e.g., hair cell damage, aging, loud noise exposure).
What is Ménière’s syndrome?
A disorder of the inner ear causing episodes of vertigo, tinnitus, hearing loss, and ear pressure due to fluid buildup.
What is a cochlear implant?
An electronic device that directly stimulates the cochlear nerve to provide hearing for individuals with severe sensorineural hearing loss.
What is equilibrium?
The body’s ability to maintain balance and spatial orientation.
What is static equilibrium?
Maintains posture and stability when the body is at rest.
What is dynamic equilibrium?
Detects motion and maintains balance when the body is in motion.
What are the receptors for both kinds of equilibrium?
Mechanoreceptors (hair cells).
What are the organs of equilibrium?
Vestibule (utricle and saccule) for static equilibrium; Semicircular canals for dynamic equilibrium.
Which cranial nerve is involved in equilibrium?
The vestibular branch of the vestibulocochlear nerve (cranial nerve VIII).
What other parts of the nervous system are involved in equilibrium?
Cerebellum, Visual system, Proprioceptors (muscles and joints), Vestibular apparatus (inner ear).
