Auditory Flashcards
Vestibulocochlear nerve is for _____ and ______
hearing
equilibrium
What is the bony labyrinth of the inner ear?
passageways in petrous temporal bone
What is the membranous labyrinth?
connective tissue tubes within bony labyrinth
What is the membranous labyrinth filled with?
endolymph (blue fluid), similar to intracellular fluid, high in K+
What is the membranous labyrinth floating in?
perilymph (similar to cerebrospinal fluid)
What is the cochlea?
organ of hearing
Define scala vestibuli
dorsal chamber
filled with perilymph
begins at oval window and spirals to apex
Define scala tympani
ventral chamber
filled with perilymph
begins at apex and ends at round window
secondary tympanic membrane
Define scala media (cochlear duct)
triangular middle chamber
filled with endolymph (K+ rich)
Stereocilia of hair cells of organ of corti are embedded in the _________
tectorial membrane
When the basilar membrane moves up, _____ are pushed into the tectorial membrane
hair cells
What is pulled that opens ion channels in the hai cell?
tip links
What ion diffuses into the hair cell and depolarizes it?
K
What is conductive deafness?
conditions interfere with transmission of vibrations to inner ear
- damaged tympanic membrane
- otitis media
- tumors, polyps
What is sensorineural (nerve) deafness?
death of hair cells, CN VIII, or any CNS system elements concerned with hearing
- genetic (congenital)
- geriatric (age-related)
- acquired (infections, trauma, loud noises, tumor)
What is the first order neuron for the auditory pathway?
cochlear n.
Where is the cochlear nuclei located?
medulla
What are 2nd order neurons of the auditory pathway?
dorsal nucleus of the trapezoid body (superior olivary nucleus) —> decussate —> DNTB or lateral lemniscus
The caudal colliculus is associated with the ______
tectospinal tract
The medial geniculate nucleus is associated with the _______
primary auditory cortex (temporal lobe)
The vast majority of signals end up in [ipsilateral/contralateral] auditory cortex
contralateral
What is the acoustic startle reflex?
reflex turning of head and neck
Trace the acoustic startle reflex pathway.
caudal colliculus in midbrain —> rostral colliculus —> to tectospinal tract —> stimulate neck muscles IPSILATERAL to sound
What nerves does the stapedius reflex involve?
vestibulocochlear n.
facial n.
Olfaction and gustation receptors are _______
chemoreceptors
What is the primary afferent neuron for olfactory receptor cells?
olfactory receptor cell
What is a gustatory receptor?
specialized epithelial cell (“sense organ”) that transducer chemical signals and then sends electrical signals to the primary afferent neuron
What does sniffing accomplish?
bring odorants into olfactory areas
Sniffing is under [unidirectional/bidirectional] flow
unidirectional flow
localize scents
expel air to purge and sniff again
The [right/left] nostril is for familiar scents, and the [right/left] nostril is for novel or noxious smells
left
right
Where do olfactory receptors only line?
olfactory epithelium on ethmoturbinates
The rest of the turbinate lining is made up of ______, with no olfactory capacity
respiratory epithelium
Olfactory epithelium has neurons exposed to ______
external environment
Define olfactory receptor cells
primary afferent neuron (bipolar)
________ bind to receptors located on cilia that protrude into the _______
odorant molecules
nasal cavity
List things in olfactory epithelium
olfactory receptor cells
supporting cells
basal cells
What is one of the only neurons that is a stem cell and CAN replace itself?
basal cells in the olfactory epithelium
Where does the odorant bind on the olfactory receptor cell?
G-protein coupled receptor
What does the G-protein subunit activate which converts ATP to cAMP?
adenylyl cyclase
cAMP opens ___, ___, and _____ channels
Na+
K+
Ca2+
The membrane in olfactory transduction is [depolarized/hyperpolarized]
depolarized
At the end of olfactory transduction, an action potential is generated in ________
olfactory neurons axon
What is the first order neuron for the olfactory path?
through cribriform plate to olfactory bulb
What do olfactory bulb interneurons do?
process, filter, enhance transmission of specific odorants
What is the 2nd order neuron in the olfactory path? Where does it go?
mitral cell
axons project to cerebellum
T/F: There is a conscious perception before the thalamus
TRUE
Where is the olfactory cortex located?
piriform lobe
In the olfactory pathway, transmission through the _____ is not required
thalamus
What is the accessory olfactory system?
vomeronasal organ that is connected to the nasal and oral cavity via the nasopalatine ducts
______ are introduced to the nasopalatine ducts through inhalation in some species and through liquid/mucus in others
pheromones
Vomeronasal organ fibers go to ______ and then to the ________
accessory olfactory bulb
olfactory cortex
What are the sensory organs for taste?
taste buds
Taste buds are found on ______
gustatory papillae
Taste buds contain what kinds of cells?
specialized epithelial cells
supporting cells
basal cells (like olfactory epithelium)
What contains chemoreceptors in the taste receptor cells?
microvilli
Bitter, sweet, or savory uses what?
G-protein coupled receptor (IP3, Ca2+)
What does the signaling cascade for bitter, sweet, and savory open?
transient receptor potential channels (TRP)
- receptor cell then depolarized
Salty has a lot of ______
Na+
Sour has a lot of _____
H+
What pathway does salty and sour use for taste transduction?
chemicals bind and directly open inotropic epithelium sodium channels to allow H+ or Na+ to enter
- receptor cells is depolarized
What are the primary afferents axons of the first order neurons in? (what nerves)
7, 9, 10
Where is the second order neuron for the gustatory pathway?
solitary nucleus of the medulla
Second order neurons send ______ to third order neurons in the ____ in the gustatory pathway
axon projections
thalamus
In the gustatory pathway, third order neurons project to the “_______” of the temporal lobe in cerebral cortex
taste cortex
seems like this pathway is ipsilateral