During head movements, what happens to the otoconia?

During head movements, what happens to the otoconia?

• A. Hair cells move
• B. Otoconia dissolve
• C. Hair cells generate signals themselves
• D. Otoconia move and stimulate hair cells

Answer: (D)

During head movements the otoconia move and stimulate hair cells. The otolithic organs sit a gel-like membrane with calcium carbonate crystals (otoconia) on top of hair cells. When the head accelerates or tilts, the otoconia, because of their inertia, lag behind the rest of the membrane and slide relative to it. That relative movement bends the stereocilia (and the kinocilium) of the hair cells, opening ion channels and altering the hair cell’s receptor potential. This transduction changes the firing rate of vestibular nerve fibers, providing the brain with information about head position and linear acceleration. The crystals don’t dissolve, and hair cells don’t generate signals on their own—they respond to mechanical deflection.

During head movements the otoconia move and stimulate hair cells. The otolithic organs sit a gel-like membrane with calcium carbonate crystals (otoconia) on top of hair cells. When the head accelerates or tilts, the otoconia, because of their inertia, lag behind the rest of the membrane and slide relative to it. That relative movement bends the stereocilia (and the kinocilium) of the hair cells, opening ion channels and altering the hair cell’s receptor potential. This transduction changes the firing rate of vestibular nerve fibers, providing the brain with information about head position and linear acceleration. The crystals don’t dissolve, and hair cells don’t generate signals on their own—they respond to mechanical deflection.