Otoliittielimiä

Otoliittielimiä, or otolith organs, are a pair of complex sensory organs located in the inner ear of vertebrates. They are responsible for detecting linear acceleration and the force of gravity, playing a crucial role in balance and spatial orientation. These organs are part of the vestibular system, which works in conjunction with the visual system to maintain equilibrium.

Each otoliittielimi consists of two main structures: the utricle and the saccule. Within these structures are specialized sensory hair cells, known as maculae. These hair cells are embedded in a gelatinous membrane. On top of this membrane are small, dense calcium carbonate crystals called otoliths, or "ear stones."

When the head undergoes linear acceleration (such as moving forward or backward, or up and down) or is tilted, the otoliths, due to their inertia, lag behind or shift relative to the underlying hair cells. This movement bends the cilia of the hair cells, generating nerve signals. These signals are then transmitted to the brain via the vestibular nerve, providing information about the direction and magnitude of the head's movement and position relative to gravity. This information is essential for maintaining posture, coordinating eye movements with head movements (vestibulo-ocular reflex), and perceiving motion.