👉 Cilia, also known as microvilli or micropinocytids, are tiny segments of epithelial cells that line the surface of the nose, throat, and mouth. Cilia play a crucial role in the process of phagocytosis (the uptake of foreign substances by the body's immune system), which is essential for the proper functioning of the respiratory system, including the lungs and trachea. Cilia are made up of microvilli that are arranged in rows