Microvilli are tiny, finger-like projections found on the surface of certain cells, particularly in the small intestine. They increase the surface area of the cell, allowing for more efficient absorption of nutrients and other substances. Each microvillus is covered by a plasma membrane and contains a core of actin filaments that help maintain its structure. These structures are essential for the function of epithelial cells, which line various organs and cavities in the body. By enhancing the surface area, microvilli play a crucial role in processes such as digestion and nutrient uptake, contributing to overall health and well-being.