Which cells are responsible for detecting linear movements and head position in the inner ear?

Which cells are responsible for detecting linear movements and head position in the inner ear?

• A. Outer pillar cells
• B. Cells of Hensen
• C. Inner pillar cells
• D. Hair cells in the maculae

Answer: (D)

The ability to detect linear movements and head position comes from the maculae of the otolith organs (utricle and saccule). These sensory epithelia contain hair cells with stereocilia and a kinocilium, sitting under a gelatinous otolithic membrane studded with otolith crystals. When the head moves linearly or tilts, the otoliths lag due to inertia, bending the hair cell stereocilia. Bending toward the kinocilium increases neurotransmitter release and vestibular nerve firing, signaling linear acceleration and gravity direction; bending away decreases firing. This mechanism specifically encodes linear movement and orientation in space. In contrast, hair cells in the cochlea (organ of Corti) and their supporting cells, including pillar cells and cells of Hensen, are involved in hearing, not detecting linear head movements. The angular-motion detectors are the hair cells in the cristae of the semicircular canals, which respond to rotational acceleration.

The ability to detect linear movements and head position comes from the maculae of the otolith organs (utricle and saccule). These sensory epithelia contain hair cells with stereocilia and a kinocilium, sitting under a gelatinous otolithic membrane studded with otolith crystals. When the head moves linearly or tilts, the otoliths lag due to inertia, bending the hair cell stereocilia. Bending toward the kinocilium increases neurotransmitter release and vestibular nerve firing, signaling linear acceleration and gravity direction; bending away decreases firing. This mechanism specifically encodes linear movement and orientation in space.

In contrast, hair cells in the cochlea (organ of Corti) and their supporting cells, including pillar cells and cells of Hensen, are involved in hearing, not detecting linear head movements. The angular-motion detectors are the hair cells in the cristae of the semicircular canals, which respond to rotational acceleration.