stereociliën

Stereocilia are specialized, finger-like projections found on the apical surface of certain epithelial cells, notably in sensory and reproductive tissues. They are composed of actin filaments, which provide structural support and flexibility. Unlike motile cilia, stereocilia do not have the machinery for movement; instead, they function primarily in sensory perception and absorption.

In the inner ear, particularly within the sensory hair cells of the cochlea and vestibular system, stereocilia form bundles that play a crucial role in mechanotransduction. When sound waves or head movements cause relative motion between the fluid and the hair cells, the deflection of stereocilia opens ion channels, initiating electrical signals that are transmitted to the brain for hearing and balance perception.

In the male reproductive system, stereocilia are present on the epithelial cells lining the epididymis and vas deferens. Here, they increase the surface area for absorption and secretion, aiding in the maturation and transport of spermatozoa.

Structurally, stereocilia are characterized by their uniform length and dense actin cross-linking. They are anchored to the underlying epithelial cells by a basal body or rootlet. Their surface may be coated with specific proteins that facilitate mechanosensation or cellular interactions.

Overall, stereocilia play a vital role in both sensory functions and epithelial transport processes. Their unique structural properties allow them to effectively sense mechanical stimuli or enhance cellular absorption, making them essential for various physiological functions across multiple organs.