Part 3 Flashcards
What are the four parts of the peripheral nervous system
Outer ear (Pinna/auricle) (localizes sound)
Middle Ear
Inner Ear
Vestibulocohlear nerve/8th cranial nerve
What are the 5 parts of the central auditory nervous system
Cochlear nucleus
Superior olivary nuclei
Lateral lemniscus
Inferior colliculus
Medial geniculate nuclei
What is the difference between afferent and efferent pathways
Afferent pathways are from ear to brain (bottom-up processing) and efferent pathways are from brain to ear (top-down processing)
What is the energy conversion through hearing
acoustic –> mechanical –> hydraulic –> electrical –> electrochemical –> electrochemical
What is bilateral phenomenon and what muscles produce it?
The tensor tympani and stapedius muscle contract at the same time for both ears no matter what unless one is damaged
What are the 4 nerves found in the auditory system
7th cranial nerve (facial nerve): controls the corda tympani and stapes muscle and bone
5th cranial nerve (trigeminal nerve)
10th cranial nerve (vagus)
8th cranial nerve: transmits sound/balance info from the middle ear to the brain
What are the 3 ossicles and where are they located?
Malleus, incus and stapes and they are in the middle ear
What is impedence matching?
Enhances signal intesnity that would’ve been lost due to the impedence mismatch created by the change from and air medium to a fluid medium (30 dB are lost if the middle ear can’t function)
Where is perilymph and endolymph fluid found
Perilymph is found in the osseous labyrinth and the membranous labyrinth contains endolymph
Where is the organ of corti located and what does it contain?
The organ of cortiis located in the cochlea and and contains outer and inner hair cells (3:1)
What protein does the outer hair cells have and what does it do
The protein is called prestin and helps inner hair cells send signals and make connections to the 8th cranial nerve
What is tonotopic organization
When the stapes vibrates the oval window and then vibrates the fluid and causes the basilar membrane to have a wavelike motion and oce the wave is at the point of maximum displacement, the inner hair cells are stimulated and secreate neurotransmitters that are sent to the 8th cranial nerve
What are the 6 relay stations in the central auditory nervous system
Dorsal/ventral cochlear nucleus
Superior olivary complex
Lateral lemniscus
Inferior Colliculus
medial geniculate body
Primary auditory cortex
What is decussation
When nerve connections cross over each other to the opposite sides and occurs at the second relay station (superior olivary complex)
What are the 5 sesnory receptors that maintain balance
Otolithic organs: utricle and saccule (horizontal/verticle acceleration)
Semicircular canals: superior, horizontal, and posterior (rotary head movement)
