Inner Ear Physiology - Fitz Flashcards
Which type of hair cells have lateral cisternae?
Type 2
Which type of hair cells are the true snesory receptors?
Why?
The type 1 cells
-they recieve 90% of afferents
-each primary afferent goes to 1 hair cell
-1 hair cells has mutliple afferents
efferents go through dendrite of primary afferent
Type 2 hair cells act a lot like:
Muscle or contractile cells
-only have 10% of afferents
Stretching the tip link between stereocilia causes:
Depolarization
This occurs when the short sterocilia bend toward the taller ones. When there is not tensiosn in the tip link, its hyperpolarized
How does adaptation occur in ahir cells?
Maintaining the tip link tnesion at proper tension to create a “set point”
Some channels always open - can always hyperpolarize
Actin/myosin unit is the mechansim by which this can be maintained
The semicircular canals detect…?
Head rotation
The otilith organs detect?
Gravity!
When inputs disagree about balance, what does thebody use as a reference?
Vestibular input!
Conflict in the body position systems will produce:
Nystagmus
Vertigo
Nausea
SEmicicrular canals are dynamic which means there is not input when….
You are at rest or in constant motion
KInocilia are found where?
NOT in the auidotry system (lose after development)
still found in the vestibular system
The orward and backward nod, with no head rotation, will activate how many semicircular canals?
4
both ant and both post
Which one of the following results from overstimulation of one semicircular canal?
Light headedness
Motion sickness
Syncope
Vertigo
Vertigo
Why does the human cochlea have the lowest thresholdsbetween 500 Hz and 5 kHz?One best answer!
1) The basilar membrane vibration has the lowest amplitude at those frequencies.
2) The basilar membrane has mass and stiffness characteristics that cause it to resonate only at those frequencies.
3) The impedance of the middle ear limits transmission of higher and lower frequencies.
4) Bone transmission is greater than air transmission at higher and lower frequencies.
3) The impedance of the middle ear limits transmission of higher and lower frequencies.
(so it’s the middle ear that allows you to hear or not hear something)
What does it mean when I say that inner ear transduction is directional?
Displacement toward the tallest sterocilia, called positive deflection, results in depolarization.
In the cochlea this happens when the basilar membrane moves toward the scale vestibuli.
When the basilar membrane moves toward the scala tympani this is called negative deflection and results in hyperpolarization!