INNER EAR Flashcards
(125 cards)
What is homeostasis
he ability of an organism or a cell to maintain internal equilibrium by adjusting its physiological processes
what is inner ear homeostasis
he process by which chemical equilibrium of inner ear fluids and tissues is maintained”
For proper inner ear function, a tight control of what is necessary
ion movement across the cell membranes
what could be disrupted if you do not have inner ear homeostasis
hair cell fxn
regulation of extracellular endolymph and perilymph
conduction of nerve impulses
The major ions involved in inner ear homeostasis include
Sodium (NA+)
Potassium (K+)
Significant roles also are played by
Chloride (Cl-)
Calcium (CA2+)
which ion channels are disrupted in connexins
potassiu
Before sound can be perceived it has to be converted to______, a process mediated by the cilia of the inner ear hair cells
electrical impulses in the auditory nerve
bring about transduction mechanism and allows nerves to integrate the signal
ihc
The sound-induced excitatory deflection of the stereocilia causes a mechanoelectrical transduction (MET) current to depolarize the hair cells and initiate _______ in the auditory nerve or vestibular nerve in response to acceleration/gravity changes
action potentials
The endolymph and perilymph are the ________ support system for hair cell function just as the cochlear partition traveling wave and tectorial membrane are the ______ support system for hair cell function
metabolic
mechanical
where is EP at its highest
it is higher at basilar end than apical end
higher in cochlear than vestibular system
high K+ concentration in the endolymph creates a +80 mV endocohlear potential (EP) that couples with a -80 mV hair cell intracellular potential to create a differential potential of +160 mV
80 mV – (-80mV) = 160 mV
Stereocilia are laterally displaced either by
Shearing movement of the tectorial membrane (outer hair cells) or
Motion of the endolymphatic fluid (inner hair cells)
what if eno and perino EP had the same ion composition?
no EP becuase there is no difference
endolymphatic hydrops - causes excessive endolymph causing the two to mix and causes the fluctuating HL in Meneire’s
specialized intercellular connection between a multitude of animal cell-types. It directly connects the cytoplasm of two cells, which allows various molecules and ions to pass freely between cells.
gap junction or nexus
Any cochlear disorder that disrupts the strial cell layers, channels, transporters, or gap or tight junctions will reduce the EP and result in a
permanent snhl
proteins embedded in the cell membrane that regulate the flow of water
aquaporins
part of the blood-brain barrier and probably the blood-labyrinth barrier
aquaporins
Active water transport b/w cells occurs through
aquaporin channels
Hearing loss can result from
increased or decreased activity of the strial process
Increased K+ transport in the endolymph or increased endolymph production
endolymphatic hydrops (too much endolymph - Meneire’s - progressive fluctuating snhl)
Decreased K+ transport in the endolymph or decreased endolymph production
endolymphatic xerosis (decrease in endolymph - connexin, JLNS - permanent snhl)
Genetic disorders associated with ion transport and pathways are often associated with
permanent hearing loss