microvilluses

Microvilluses are microscopic finger-like projections that extend from the surface of certain cells. These structures are typically found on epithelial cells, which line surfaces within the body. Their primary function is to increase the surface area available for absorption and secretion. The increased surface area is crucial for processes like nutrient absorption in the intestines and reabsorption of substances in the kidneys. Microvilli are composed of actin filaments, which provide structural support and enable some limited movement. They are often referred to collectively as a "brush border" when densely packed on a cell's surface. The membrane covering microvilli contains transport proteins that facilitate the movement of molecules across the cell. While similar in appearance to cilia, microvilli are structurally distinct and lack the microtubule core characteristic of cilia and flagella. Their presence significantly enhances the efficiency of cellular functions that rely on exchange with the external environment.