Cilia

Definition

Cilia are hair-like structures on the surface of eukaryotic cells that facilitate movement and sensory functions. They play vital roles in cell motility, fluid movement, and signaling.

5 Must Know Facts For Your Next Test

1. Cilia are composed of microtubules arranged in a '9+2' structure.
2. They can be classified as motile or non-motile (primary cilia) based on their function.
3. Motile cilia are found in large numbers on the cell surface and help propel fluids across epithelial surfaces.
4. Non-motile primary cilia typically act as sensory organelles, detecting environmental signals.
5. Defects in ciliary structure or function can lead to diseases known as ciliopathies.

Review Questions

• What is the structural arrangement of microtubules in cilia?
• How do motile and non-motile cilia differ in function?
• What types of diseases can arise from defects in ciliary function?

Related terms

Microtubules:

Cylindrical structures made of tubulin proteins that form the core of cilia.

Flagella:

Long, whip-like appendages used for cell movement, similar to but usually longer than cilia.

Basal Body: The organelle that forms the base of a cilium or flagellum and organizes its microtubules.