ciliaaflagellia

Cilia and flagella are organelles found in eukaryotic cells that are responsible for motility. While they share a similar internal structure, they differ in length and number. Cilia are typically short and numerous, covering the surface of a cell, whereas flagella are longer and fewer in number, often just one or two per cell. Their primary function is to propel the cell through its environment. For single-celled organisms like some protists, this movement is essential for locomotion and finding food. In multicellular organisms, cilia and flagella have specialized roles. For example, in the respiratory tract, cilia beat in a coordinated fashion to move mucus and trapped particles away from the lungs. In sperm cells, a single flagellum provides the propulsion needed to reach the egg. The internal structure of both cilia and flagella is characterized by a "9+2" arrangement of microtubules. Nine doublet microtubules surround a central pair of single microtubules, a highly conserved arrangement across eukaryotes. This structure allows for the bending and whipping motions necessary for their propulsive function, powered by the motor protein dynein. Damage to cilia or flagella can lead to various health issues, highlighting their importance in cellular and organismal function.