Vestibular System Anatomy and Function: Key Concepts for Balance and Equilibrium

What are the two primary roles of the vestibular system?

To maintain a useful visual field as the head moves and to maintain body position (balance and posture) as the head moves.

What is the functional classification of the vestibular system?

It is classified as Special Somatic Afferent (SSA) and Special Proprioception (SP).

What are the components of the bony labyrinth in the vestibular apparatus?

The bony labyrinth includes the semicircular canals and the vestibule.

What is found inside the bony labyrinth?

The membranous labyrinth, which contains specialized receptors.

What fluids are present in the vestibular apparatus?

Perilymph in the bony labyrinth and endolymph in the membranous labyrinth.

What is the function of the hair cells in the vestibular system?

They detect rotary movement of the head and the pull of gravity, as well as linear movement.

Where are the hair cells located that detect angular movement?

In the ampulla of a semicircular duct, specifically in the crista ampullaris.

What is the gelatinous material that hair cells are embedded in called?

Cupula.

What is the function of the macula in the vestibule?

To detect linear movement and static equilibrium in a horizontal position (in the utricle) and vertical orientation (in the sacculus).

What happens to hair cells when the head moves?

The endolymph moves, which in turn moves the gel and bends the hair cells.

What is the role of the vestibular ganglion?

To send information to other areas for appropriate responses in body or eye movement.

What are the two areas where hair cells are located in the vestibular system?

In the ampulla of the semicircular duct (crista ampullaris) and in the utricle and sacculus (macula).

What type of equilibrium does the macula in the sacculus detect?

Static equilibrium, which includes forward, backward, and up/down movements.

What type of equilibrium is detected by the crista ampullaris?

Dynamic equilibrium, related to angular movement.

What is the relationship between hair cells and nerve fibers in the vestibular system?

Movement of the hair cells stimulates the vestibular nerve fibers.

What is the significance of the endolymph in the vestibular system?

It bathes the hair cells and facilitates their movement in response to head motion.

What is the anatomical structure that connects the vestibular system to the brain?

Vestibular fibers synapse on the four pairs of vestibular nuclei.

What is the role of supporting cells in the vestibular system?

To provide structural support for the hair cells and other components.