Sacculus

Sacculus is a component of the vestibular system, which contributes to our sense of balance and spatial orientation. The sacculus is one of two otolith organs located in the vestibule of the inner ear, the other being the utricle. These organs are responsible for detecting linear accelerations and head tilts in relation to gravity.

Structure

The sacculus is a small, vertically oriented sac near the base of the vestibule. It is connected to the cochlear duct via the ductus reuniens. The sacculus contains a macula, a sensory epithelium that responds to changes in head position and linear acceleration. The macula consists of hair cells and supporting cells. The hair cells are covered by a gelatinous layer called the otolithic membrane, which contains small calcium carbonate crystals called otoliths. When the head moves, the otoliths shift, causing the hair cells to bend and send signals to the brain about the head's movement.

Function

The primary function of the sacculus is to detect vertical acceleration, such as when we move up and down. It also contributes to our perception of loud sounds. The hair cells in the sacculus are activated by the movement of the otoliths, which send signals to the brain via the vestibular nerve. These signals are interpreted by the brain as changes in position or movement.

Clinical significance

Damage to the sacculus can result in a variety of balance disorders, including vertigo, dizziness, and problems with spatial orientation. In addition, because the sacculus is connected to the cochlea, damage can also affect hearing.

See also

• Vestibular system
• Utricle
• Otolith