Week 3 Flashcards
(46 cards)
What are the 2 otolith organs?
- Utricle
2. Saccule
What are the names of the 3 semi-circular canals
- Horizontal (Lateral)
- Anterior (Superior)
- Posterior
Semi-Circular Canals sense what type of acceleration?
Angular Acceleration - moving head to side to side
Otolith Organs sense what type of acceleration? Give 2 examples
Linear acceleration
- Changing head position from laying to standing
- Gravity change, riding on elevator
What are the two structures inside the SCC?
Ampula and Cupula
What structure contains the hair cells?
Cupula
What is present in the utricle and saccule that contain crystals and allow one to judge gravity?
Macula
WIT: A swelling at the entrance of each Semi-circular canal? What does it contain?
Ampula, contains a cupula
What specific feature causes the SCCs to only be responsive to angular acceleration?
The cupula and endolymph are the same density
Stimulation from sterocilia to kinocilia = ?
Excitatory,
- depolarization causing increased firing of VN
Stimulation from kinocilia to sterocilia = ?
inhibitory
-hyperpolarization, decreased firing of CN
What is the 3 neuron arc for horizontal VOR?
- SCC
- Vestibular Nuclei
- OMN (abducens + oculomoter)
The head velocity signal is generated by what?
SCC
What are the neural integrators for horizontal conjugate eye movements?
MCN
NPH
The utricle presents on what plane?
Horizontal Plane
The saccule presents on what plane?
Vertical Plane
The presence of what increases the density of the gelatinous material of the macula, allowing for gravitational changes to be sensed?
Calcium Carbonate Crystals (called Otoconia)
Translational VOR is induced when stimulated by what otolith?
Utricle
Ocular Counter-Rolling is indiced by the stimulation by which otolith?
Saccule
What specific sensory structures are being activated when riding in an elevator?
t-VOR, utricle
What is themost common cause of dizziness? What is this called?
When calcium carbonate crystals from utricle migrate into the posterior SCC
BPPV = Benign Paroxysmal Positional Vertigo
Kinocilia of the Utricle are oriented where?
Towards the striola in the center
Kinocilia of the Saccule are oriented where?
Away from the striola/center,
What are the 3 parts of the 8th cranial nerve?
- Cochlear
- Inferior vestibular
- Superior vestibular