Primary cilium

The primary cilium is a small, hair-like structure that protrudes from the surface of most cells in the body. It acts like an antenna, detecting signals from the cell’s environment and helping coordinate important functions such as growth, development, and communication between cells. Unlike the many tiny hair-like structures that move, the primary cilium is usually static and specialized for sensing. It plays a vital role in maintaining healthy cell function, and defects in its structure or signaling can lead to various diseases known as ciliopathies.