The saccule is a small membranous sac located in the vestibule of the inner ear, paired with the utricle.It is part of the membranous labyrinth and plays an important role in orientation and balance, specifically in vertical tilt. 

What is Saccule and Utricle?

The saccule and utricle are two small, sac-like structures located in the vestibule of the inner ear. They are part of the vestibular system, which is responsible for balance and spatial orientation.

What is the Function of Otolith and Saccule?

The otoliths are small, calcium carbonate crystals that are embedded in the gelatinous otolithic membrane of the saccule and utricle. When the head moves, the otoliths move with it. This movement bends the otolithic membrane, which sends signals to the brain about the direction and magnitude of head movement.

What is Saccule Composed Of?

The saccule is composed of three parts:

  • The saccular macula: This is a patch of hair cells that are embedded in the otolithic membrane.
  • The saccular duct: This is a fluid-filled canal that runs through the saccule.
  • The saccular sac: This is the saccule’s outer layer.

What is the Action of Utricle and Saccule?

The utricle and saccule work together to sense linear acceleration, which is the movement of the head in a straight line. When the head moves forward, the otoliths in the utricle move forward, bending the otolithic membrane. This sends a signal to the brain that the head is moving forward. The saccule works in a similar way, but it senses movement in the vertical plane.