What is "stereocilia"

n. (plural of stereocilium English)

In the inner ear, stereocilia are the mechanosensing organelles of hair cells, which respond to fluid motion in numerous types of animals for various functions, including hearing and balance. They are about 10–50 micrometers in length and share some similar features of microvilli. The hair cells turn the fluid pressure and other mechanical stimuli into electric stimuli via the many microvilli that make up stereocilia rods. Stereocilia exist in the auditory and vestibular systems.

Stereocilia (or stereovilli) are non-motile apical modifications of the cell, which are distinct from cilia and microvilli, but closely related to the latter.

In structure, they are longer than typical microvilli, and have more of the characteristics of the cellular membrane proper. Like microvilli, they contain actin filaments, distinguishing them from microtubule-containing cilia.

They are found in three regions of the body:

• the ductus deferens
• the epididymis (see stereocilia (epididymis) for more details). Some sources consider epididymal stereocilia to be a variant of microvilli, rather than their own distinct type of structure.
• the sensory (hair) cells of the inner ear (see stereocilia (inner ear) for more details)