Cilia: Structure, Function, Definition

The cytoskeleton is a redesigned fibrous proteinaceous framework found in the cytoplasm of the cell. It provides mechanical support to cells. It also assists the cell in maintaining its own form and movement.

Microtubules are also called tubulin polymers. Their diameter is around 25 nanometers. The main function of this fiber is to preserve the shape of cells. It also aids with cell mobility, for instance, the motion of the chromosomes during cell division.

Cilia are hair-like organelles made up of microtubules that protrude from the exterior of practically all human cell types. During development, morphogenesis, and homeostasis, they have been developed as adaptable tools for numerous tissue-specific roles, including such motile and sensory.

Definition:

Cilia are hair-like protrusions from the cell membrane. Cilia are tiny structures that act, such as oars, allowing the cells or surrounding fluid to travel. The singular form of Cilia is the cilium.

Structure of cilia:

1. Cilia are shorter than flagella, measuring 5 µm to 10 µm in diameter compared to 15 µm for flagella.
2. Each cell structure has roughly 100 cilia.
3. They are membrane-bound and protrude protoplasmically.
4. An electron microscope examination reveals that it is surrounded by a plasma membrane.
5. Cilia are mainly composed of microtubules of the contractile protein tubulin.
6. Multiple microtubules make up the cilia’s core.
7. Lengthways, these microtubules extend. The axoneme is the name for the core.
8. There are nine pairs of peripheral microtubule doublets organized radially in the axoneme.
9. In the center, there are two (a pair of) microtubules.
10. The microtubules are arranged in a 9 + 2 pattern, with two central microtubules and nine duplet sets around them.

Cilia are divided into two types:

Actively motile cilia:

1. They are cell processes that are 7 µm to 10 µm long and extend from particular epithelia.
2. They’re set up in a 9+2 layout.
3. Dynein arms, radial spokes, Nexin and Tekin, are some of the other components.

Primary cilium:

1. It is also known as nonmotile cilium.
2. It is found in the majority of human cells at the G0 stage of the cell cycle.
3. They are thought to play a crucial role in the structure of signaling pathways both during embryonic development and in adulthood.
4. They’re thought to be dormant evolutionary leftovers.
5. They feature a 9+0 structure, unlike motile cilia.

The function of Cilia:

1. Cilia are used by some unicellular organisms, such as Paramecium, to swim in the water.
2. Some biological tissues in multicellular organisms, such as epithelial tissues, have cilia.
3. The current in the fluid is produced by beating in the fluid that enables it to travel in a specific direction, such as pushing mucus and dust particles out of the windpipe or trachea.
4. Cilia beat like a boat’s little oars or pedals.