Cilia

Definition

Cilia are small, hair-like structures on the surface of eukaryotic cells. They play roles in movement and sensory functions.

5 Must Know Facts For Your Next Test

1. Cilia can be motile or non-motile, with motile cilia involved in cell movement and fluid movement across cell surfaces.
2. Non-motile cilia, also called primary cilia, act as sensory organelles.
3. Cilia are composed of microtubules arranged in a '9+2' structure for motile cilia and a '9+0' structure for non-motile cilia.
4. Defects in ciliary function can lead to diseases known as ciliopathies, such as Primary Ciliary Dyskinesia.
5. The coordinated beating of motile cilia is essential for processes like clearing mucus from the respiratory tract.

Review Questions

• What are the two main types of cilia and their functions?
• Describe the microtubule arrangement in motile and non-motile cilia.
• How do defects in ciliary function affect human health?

Related terms

Microtubules: Structural components of cilia made up of tubulin proteins arranged in specific patterns.

Flagella:

Long, whip-like structures used for cell movement that share a similar structural composition with cilia.

Basal Body: The organelle that forms the base of a cilium or flagellum, anchoring it to the cell membrane.