Chapter 11: The Auditory and Vestibular Systems Flashcards
Sense of hearing: ()
audition
Sense of balance: ()
vestibular system
visible portion of the ear; consists of cartilage covered by skin -> forms a sort of funnel that helps collect sound from a wide area
pinna
shape of pinna makes us more sensitive to sounds (ahead/behind) us
ahead
Entrance to internal ear
auditory canal
End of auditory canal
tympanic membrane
Series of bones (smallest bones in the body)
ossicles
ossicles transfer movements of tympanic membrane into movements of () -> 2nd membrane; covers a hole in the skull
oval window
fluid-filled compartment located behind oval window; contains apparatus for transforming physical motion of oval window membrane into a neuronal response
cochlea
() in the cochlea send signals to brain stem neurons in response to sound detection
auditory receptors
in response to signals from cochlea, brain stem neurons then bring info to ()
medial geniculate nucleus (MGN)
MGN projects to () located in temporal lobe
primary auditory cortex (A1)
bones classified as ossicles
- malleus (hammer)
- incus (anvil)
- stapes (stirrup)
ossicle connected to tympanic membrane and incus
malleus
the incus forms a (rigid/flexible) connection to stapes
flexible
the stapes has a flat bottom portion called a ()
footplate
Connects air in middle ear and air in nasal cavities
Valve keeps it closed; opening of valve equalizes air pressure between middle ear and nasal cavities
Eustachian tube
Response when onset of loud sound causes tensor tympani and stapedius muscle contraction (makes the chain of ossicles become rigid)
attenuation reflex
(): anchored to Malleus on one end and the cavity of the middle ear on the other end
Tensor tympani muscle
(): a fixed anchor of bone and stapes
Stapedius muscle
function of the attenuation reflex
adapts ear to loud sounds, protects inner ear, enables us to understand speech better
When ossicles chain becomes rigid, sound conduction to inner ear is greatly (amplified/diminished)
diminished
Three fluid-filled chambers of the cochlea
Scala vestibuli
Scala media
Scala tympani
() – separates s. vestibuli and s. media in cochlea
Reissner’s membrane
() – separates s. tympani from s. media in cochlea
Basilar membrane
()– holes in membranes; connects s. tympani and s. vestibuli in cochlea
Helicotrema
() – contains auditory receptor neurons in cochlea
Organ of Corti
() membrane – located above Corti
Tectorial
(): fluid in scala vestibuli and scala tympani (low K+ and high Na+: similar to CSF)
Perilymph
(): fluid in scala media (high K+ and low Na+: similar to intracellular fluid)
Endolymph
(): endolymph electrical potential 80 mV more positive than perilymph
Endocochlear potential
the Endocochlear potential is caused by ()
Caused by ion difference and permeability of Reissner’s membrane
() – endothelium lining one wall of the scala media; contacts the endolymph; Where active transport processes take place to maintain different ion contents between perilymph and endolymph
Stria vascularis
stria vascularis absorbs (1) from and secretes (2) into endolymph
- Na+
- K+
At high freq., stiffer base of membrane vibrates -> ()
dissipates most of the sound energy and wave doesn’t travel very far
() sounds generate waves that travel all the way to the floppy apex before energy is dissipated
Low freq.
The response of basilar membrane establishes a place code in which ()
different location of membrane are maximally deformed at different sound frequency
Systemic organization of sound frequency within the auditory structure: ()
tonotopy
Specialized epithelial cells with stereocilia
hair cells