Module 3.2 Auditory and Vestibular System Flashcards
What is the purpose of the auricle?
The auricle is shaped to funnel sound waves into the external acoustic canal so that sounds can be detected.
What is the purpose of cerumen?
Earwax which serves to trap foreign materials.
The inner end of the external acoustic meatus terminates at the _____?
Tympanic membrane.
What bone touches the inner ear to transmit vibrations?
Stapes.
The semicircular canals contribute in this way to the body’s_____ sense.
Vestibular sense.
The ______ is the sense organ for the auditory system.
Organ of Corti.
The movement of the stereocilia stimulates the neurons to send impulses through the _____ nerve to the _______ lobe of the brain.
Cochlear nerve; temporal lobe.
What is unique about the way the auditory pathway travels to the brain?
The auditory pathway is a unique sensory pathway because the ascending pathways cross in addition to sending signals to the same side of the brain. The result is that sounds from each ear are equally interpreted on the left and right sides of the brain.
What is the difference between nerve deafness vs. conduction deafness?
Conduction deafness occurs from damage to the outer or middle ear structures. Nerve deafness occurs from damage to the nerve pathway.
What are the 3 areas of the ear?
External, middle, and inner ear.
What makes up the external ear?
The auricle and external acoustic meatus.
What makes up the auricle?
The rim (helix) and the lobule, consist of elastic cartilage covered with skin.
What is the middle ear?
Aka the tympanic cavity, is air-filled and contains the malleus, incus, and stapes.
What kind of structures make up the inner ear?
Bony membranous labyrinths filled with fluid.
What 3 sections is the bony labyrinth system divided into?
The vestibule, semicircular canals, and cochlea.
Which connected structures create the vestibular system?
The vestibule and the semicircular canals.
What do the vestibule’s receptors detect?
Movement in straight line. up-down and front-back movements. Upright orientation, acceleration and head changes in position to gravity
What do the semicircular canal receptors detect and why?
Head movements/rotation (turning, shaking, tilting) because the 3 canals are on different planes
How is CN VII involved with the inner ear?
It innervates the stapedius which controls tension on the stapes bone which allows increased/decreased tension according to sound intensity.
What is the cochlea?
Spiral, bony chamber containing the membranous endolymph-filled cochlear duct which houses the organ of Corti and terminates at the cochlear nerve.
What does the organ of corti contain?
Tectorial membrane and stereocilia.
How is sound transmitted in cochlea to the cochlear nerve?
Fluid in cochlear duct receives vibrations, the tectorial membrane moves/bends the attached stereocilia. The mechanical movement initiates an action potential in neurons that is transmitted through the cochlear nerve portion of CN VIII.
What is the auditory pathway?
Sound waves > external auditory canal > eardrum to vibrate > ossicles > fluid inside the cochlear duct > movement of stereocilia > stimulates neurons > impulses through cochlear nerve > primary auditory cortex of the temporal lobe.
