Round Pouch

Round pouch

The round saccule is a small cavity in the inner ear, lined with sensitive hair cells and containing tiny crystals of calcium carbonate. The round sac contains receptors responsible for the feeling of static balance.

The round pouch is located in the vestibule of the inner ear. It has a round shape and is filled with endolymph, a fluid similar in composition to the intercellular fluid. On its inner surface there is a spot containing receptor cells with hair-like processes. These processes are sensitive to head position and movements.

When tilting or turning the head, calcium carbonate crystals are displaced relative to the receptor cells, which leads to their irritation. Excitation of the receptors is transmitted to the brain, where a sense of the body’s position in space is formed. Thus, the round pouch plays an important role in maintaining balance and spatial orientation.