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Questions and Answers
What is the primary function of the vestibular ocular reflex?
What is the primary function of the vestibular ocular reflex?
Which axis corresponds to forward and backward movement in the context of linear translation?
Which axis corresponds to forward and backward movement in the context of linear translation?
Which type of rotation does the term 'roll rotation' refer to?
Which type of rotation does the term 'roll rotation' refer to?
What do the otolith organs primarily sense?
What do the otolith organs primarily sense?
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What is the shape and firing pattern of Type 1 hair cells at rest?
What is the shape and firing pattern of Type 1 hair cells at rest?
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What happens to the firing rate of hair cells when stereocilia bend toward the kinocilium?
What happens to the firing rate of hair cells when stereocilia bend toward the kinocilium?
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Which structure within the semicircular canals contains the vestibular hair cells?
Which structure within the semicircular canals contains the vestibular hair cells?
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How does the push-pull arrangement of the semicircular canals function?
How does the push-pull arrangement of the semicircular canals function?
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What is the primary factor that causes changes in the firing rate of canal hair cells?
What is the primary factor that causes changes in the firing rate of canal hair cells?
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What role do otoconia play in the function of the otolith organs?
What role do otoconia play in the function of the otolith organs?
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What occurs to the firing rate of hair cells during prolonged constant rotation?
What occurs to the firing rate of hair cells during prolonged constant rotation?
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Which of the following statements reflects the directional sensitivity of the semicircular canals?
Which of the following statements reflects the directional sensitivity of the semicircular canals?
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How do the otolith organs differentiate between linear acceleration and gravity?
How do the otolith organs differentiate between linear acceleration and gravity?
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Which rotation refers to the movement around the x-axis?
Which rotation refers to the movement around the x-axis?
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The vestibular ocular reflex stabilizes vision by moving the eyes in the same direction as the head.
The vestibular ocular reflex stabilizes vision by moving the eyes in the same direction as the head.
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The three axes of linear translation are defined relative to our head and include the x, y, and ______ axes.
The three axes of linear translation are defined relative to our head and include the x, y, and ______ axes.
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Match the following terms with their corresponding definitions:
Match the following terms with their corresponding definitions:
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What is the result when stereocilia bend away from the kinocilium?
What is the result when stereocilia bend away from the kinocilium?
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Each semicircular canal has a unique axis of rotation that is independent of the other canals.
Each semicircular canal has a unique axis of rotation that is independent of the other canals.
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What structure is housed within the ampulla of each semicircular canal?
What structure is housed within the ampulla of each semicircular canal?
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The otolith organs detect ______ acceleration and gravity.
The otolith organs detect ______ acceleration and gravity.
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Match the following parts of the vestibular system with their main functions:
Match the following parts of the vestibular system with their main functions:
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How does the firing rate of hair cells during sudden acceleration change?
How does the firing rate of hair cells during sudden acceleration change?
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The cilia of hair cells in the otolith organs are embedded within a gelatinous layer with crystals.
The cilia of hair cells in the otolith organs are embedded within a gelatinous layer with crystals.
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What does the push-pull arrangement in the vestibular system refer to?
What does the push-pull arrangement in the vestibular system refer to?
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Study Notes
Vestibular Sensation
- Sense of self-motion and orientation
- Balance
- Stabilizes vision during head movement
- Vestibular ocular reflex: eyes move opposite to head movement
Linear Translation
- Axes relative to the head, not gravity
- X-axis: forward movement (through the nose)
- Y-axis: side-to-side movement (through the ears)
- Z-axis: up and down
Rotation
- Roll rotation: around the x-axis (side-to-side)
- Ear towards shoulder
- Pitch rotation: forwards and backwards around the y-axis
- Example: nodding yes/no
- Yaw rotation: turning on the spot around the z-axis
- Example: shaking head "no"
Inner Ear
- Three semicircular canals (anterior, horizontal, posterior)
- Sense rotational movement (roll, pitch, yaw)
- Filled with endolymph
- Otolith organs: utricle and saccule
- Sense linear translation and gravity
- Sense gravitational force
- X, Y, Z axes
Hair Cells
- Receptors in the cristae of semicircular canals and maculae of otolith organs
- Embedded in gelatinous medium
- Two types
- Type 1: bulbous shape, irregular firing pattern at rest
- Type 2: elongated shape, regular firing pattern at rest
- Stereocilia bending changes firing rate
- Toward kinocilium (tallest stereocilium): increase firing rate
- Away from kinocilium: decrease firing rate
Vestibular Transduction
- Semicircular canals
- Contain crista with vestibular hair cells
- Hair cells aligned in the same direction
- Three canals per side, arranged orthogonally
- Push-pull arrangement: one side's push creates equal pull on the other
- Same rotation direction increases firing rate on one side, decreases on the other
- Directional sensitivity
- Each canal sensitive to rotations
- Rotations around other axes do not trigger movement
- Detect rotations close to preferred axis
- Sum total of all rotations to determine the final response
- Dynamic Response
- Firing rate proportional to angular velocity
- Sudden changes in acceleration (e.g., sudden starts/stops) lead to sudden changes in firing rate
- Constant rotation leads to subsidence of cupula movement, and firing returns to baseline after ~15 seconds.
- Opposite happens when rotation stops
- Otolith Organs
- Utricle and saccule (each), containing hair cells and otoconia (calcium crystals)
- Sense linear acceleration, gravity, movement direction
Otolith Dynamics
- Constant tilt (or acceleration) proportional firing rate
- Movement in preferred direction bends stereocilia toward kinocilium = increase firing rate
- Movement in opposite direction bends stereocilia away from kinocilium = decrease firing rate
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Description
Test your knowledge on vestibular sensation, including the sense of self-motion and balance. This quiz covers the mechanics of linear translation, rotation, and the role of the inner ear structures. Dive into the fascinating world of how we perceive movement and orientation.
