Vestibular System Anatomy & Physiology Techniques Flashcards
7 cards from real CVT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Vestibular System Anatomy & Physiology Techniques flashcards as text
The posterior semicircular canal is most sensitive to head movements in which plane?
Answer: Sagittal (pitch) plane
The posterior semicircular canal lies in a plane roughly parallel to the sagittal plane and responds primarily to pitch (nodding) head movements.
Which of the four vestibular nuclei is primarily involved in the vestibuloспinal reflex controlling trunk and limb muscles?
Answer: Lateral vestibular nucleus (Deiters)
The lateral vestibular nucleus (Deiters' nucleus) gives rise to the lateral vestibulospinal tract, which facilitates ipsilateral extensor muscles for postural stability.
Otoconia are primarily composed of:
Answer: Calcium carbonate (calcite) crystals in a glycoprotein gel
Otoconia are dense calcium carbonate crystals embedded in a gelatinous glycoprotein matrix (otolithic membrane) overlying the macula.
The medial vestibulospinal tract primarily coordinates:
Answer: Neck and upper limb muscles for head stabilization
The medial vestibulospinal tract descends in the MLF to cervical and upper thoracic levels, coordinating neck and upper limb muscles to stabilize the head.
In BPPV of the posterior canal, the Dix-Hallpike maneuver typically elicits nystagmus that is:
Answer: Torsional-upbeat, geotropic, and fatigable
Posterior canal BPPV produces torsional-upbeat (geotropic top pole beating toward affected ear) nystagmus that is fatigable with repeated testing due to canalith repositioning.
Which structure regulates endolymph volume and composition through active ion transport?
Answer: Stria vascularis (in cochlea) and dark cells (in vestibule)
The stria vascularis in the cochlea and analogous dark cells in the vestibular labyrinth actively pump ions to maintain the high-K⁺ endolymph composition.
The tilt of the head to one side causes the utricle macula to detect gravity because otoconia deflect the:
Answer: Stereocilia toward or away from the kinocilium depending on tilt direction
Head tilt shifts the weight of otoconia, bending stereocilia either toward or away from the kinocilium depending on the direction of tilt, resulting in excitation or inhibition.