The vestibular system Flashcards
What is the primary function of the vestibular system?
Provides information concerning gravity, rotation, and acceleration
It serves as a reference for the somatosensory & visual systems.
What are the two main components of the vestibular system?
Semicircular canals and otoliths
The semicircular canals are responsible for detecting head rotation, while the otoliths sense head tilt and linear acceleration.
How do the semicircular canals transduce head rotation into neural signals?
The structure of the canals and the position and orientation of hair cells in the ampulla allow for transduction
Fluid movement in the canals displaces the cupula, bending the hair cells.
What do the otoliths transduce?
Head tilt and linear acceleration
The saccule and utricle are the specific components involved in this transduction.
What questions does the vestibular organ help answer?
Where am I going? Which way is up?
This is achieved by sensing head angular acceleration, head rotation, and gravity.
What are the three degrees of freedom in three-dimensional movement?
Translational (linear movements) and rotational (body rotation)
Translational movements occur along the x, y, and z axes, while rotational movements occur around these axes.
What is the role of the peripheral sensory apparatus in the vestibular system?
Detects and relays information about head angular and linear velocity
It orients the head with respect to gravity.
What is the function of the central processing system in the vestibular system?
Processes information in conjunction with other sensory inputs
It determines the position and movement of the head in space.
What is the vestibulo-ocular reflex (VOR)?
Keeps the eyes still in space when the head moves
It allows objects to remain in focus during head movements.
What are the three major vestibular reflexes?
Vestibulo-ocular reflex, vestibulo-colic reflex, vestibular-spinal reflex
These reflexes maintain clear and stable vision and adjust posture during changes in position.
How does alcohol affect the vestibular system?
Alcohol decreases the density of the cupula, causing it to float more
This results in the sensation of rotation even when the person is still.
Fill in the blank: The semicircular canals are filled with _______.
Endolymph
This fluid movement is crucial for the detection of angular acceleration.
True or False: The utricle is most sensitive to tilt when the head is horizontal.
False
The utricle is most sensitive to tilt when the head is upright.
What is the striola in the otolith organs?
A structural landmark that arranges otoconia into narrow trenches
It divides the hair cells into two populations with opposing polarities.
What happens to hair cell cilia during head movements?
Cilia are displaced towards the kinocilium, causing depolarization
This mechanism is similar to that in the cochlea.
What is the role of the vestibular nerve?
Relays signals from the vestibular organs to the central nervous system
It includes tonic signals related to head velocity and acceleration.
