The<unk>  is a filamentous structure found at the apical surface of epithelial cells that possess microvilli. It is composed primarily of actin filaments stabilized by spectrin, which also anchors the<unk>  to the apical cell membrane. The presence of myosin II and tropomyosin helps to explain the contractile ability of the<unk> . When contracted, the<unk>  causes a decrease in diameter of the apex of the cell, causing the microvilli, which are anchored into the<unk>  through their stiff actin fibers, to spread apart. This spreading apart of the microvilli aids cells in absorption.
Terminal web
Beevor's axiom
Cradle cap
Pocock boundary
Hippocratic bench
Apex 
Ossification center
Floor plate