APA Dictionary of Psychology

n. (pl. microvilli) a slender, minute structure projecting from the surface of a cell. For example, in taste perception, a microvillus is the hairlike extension of each taste cell that projects through the pore of a taste bud to sample the environment. Although a microvillus accounts for only 3% of the surface area of a taste cell, it is studded with receptor proteins that recognize specific molecules and is the site of taste transduction.