Cilia vs. Microvilli: cilia and microvilli are two different projections present within the plasma membrane. These can also be found on the outermost surface of the epithelial cells. But if we talk about microvilli vs. cilia difference, both perform different functions in the cells. Moreover, both of these have their own different structure and location.
Let’s take a closer look at Microvilli versus Cilia
| Motility | Cilia are motile while microvilli are non-motile |
| Absorption | Only microvilli can facilitate absorption |
| Amount | The amount of microvilli is larger than cilia |
| Length | Cilia are longer as compared to microvilli |
Table of Contents
What is Cilia?
Cilia are long hair-like projections present on the plasma membrane and made up of microtubules. Cilia can also be found in some specialized cells like sensory cells of ears, which are responsible for the initial sensory input of hearing. The length of each cilium is between 5 to 10um and has a diameter of 0.2 um. Cilia are motile and beat in one direction to move the entangled particles from the surface. If we look at the structure of cilium, it is made up of microtubules arranged in a longitudinal orientation. This orientation is also known as 9+2 orientation which means each cilium has nine microtubule doublets which are located peripherally with two microtubules in the center. The function of motile cilia is to move water relative to cells.
What is Microvilli?
Microvilli are finger-like projections present on the cell membrane, increasing cells’ surface area. It is mostly found in the small intestine, the surface of white blood cells, and egg cells. If we look at the structure of microvilli, each microvillus is formed by microfilaments which are held together by cross-linking of protein. Some bundling proteins like spin, violin, and fimbrin are involved in the cross-linking of this microfilament. Microvilli are smaller and narrower as compared to cilia. Their length is between 0.5 and 1.0 um, and their width is 0.1. The main function of the microvilli is to increase nutrient absorption in the small intestine. These also facilitate carbohydrate digestion. Microvilli present on the egg cell surface allow the anchoring of sperm cells with egg cells, and microvilli on white blood cells make them migrate.
6 key Differences Between Cilia and Microvilli
| Components | Cilia | Microvilli |
|---|---|---|
| Structure | Cilia are made up of microtubules that are coated by a plasma membrane. Each cilium makes an axoneme structure in which nine pairs of microtubules form an outside ring with two central microtubules. | Microvilli are small finger-like projections that are 90nm in diameter and 1mm in length. In microvilli, bundles of parallel actin filaments are held together through a cross-linking protein, fimbrin, and villin. These proteins held them in a bundle. |
| Function | The main function of cilia is to move water relative to the cell. Multiple cilia move In a rhythmic motion and keep the internal passageways free from any kind of foreign agent or mucus. | Microvilli on the surface of epithelial cells increase the cell’s surface area and facilitate the absorption of water molecules and ingested food. |
| Types | Cilia can be divided into two types: motile and non-motile cilia. Non-motile cilia are also known as primary cilia. | Microvilli are divided into three types according to their function: absorptive microvilli, microvilli for immune cells, and microvilli for inner ear cells. |
| Location | Motile cilia are located on the epithelial cells of several organs like the lungs, digestive system, and trachea. And non-motile cilia can be found on olfactory neurons. | A thousand amounts of microvilli can be found on the apical surface of human small intestine cells. It can also occur in cells of taste buds and cells of the inner ear. |
| Glycocalyx | Cilia shafts are not covered with glycocalyx. Each cilium is covered with a cell membrane and originates near a basal body. | Microvilli are covered with glycocalyx, which contains peripheral glycoproteins to attach themselves to the membrane. |
| Ultra Structure | In the ultrastructure of cilia, cilia show a few subregions, which are transition zones to link these cilia to a basal body. | In the ultrastructure of microvilli, each microvillus consists of a bundle of actin filaments, which work as its structural core. |
Cilia vs. Microvilli Similarities
- Cilia or microvilli both are microscopic structures that are present in the plasma membrane.
- Both grow outside of the cells
- Both consist of protein fiber
Cilia vs. Microvilli Pros and Cons
Cilia Pros and Cons
Pros of Cilia
- Motile cilia present in the respiratory tract and inner ear keep the inner passage clear from dirt and mucus by their rhythmic movement.
- Cilia also plays an important role in human and animal replication and cell cycle.
Cons of Cilia
- If cilia are not working properly due to some reason, it can result in remaining bacteria in the respiratory tract and cause infection.
- Damage to cilia can make breathing difficult and cause respiratory issues.
Microvilli Pros and Cons
Pros of Microvilli
- Microvilli can increase the cell’s surface area, which improves absorption and secretion function.
- In the intestine, microvilli can help in absorbing more nutrients and material as it expands the intestine’s surface area.
Cons of Microvilli
- Damaged microvilli can result in intestinal malfunction, which leads to several issues like diarrhea.
- Gluten-containing products with celiac diseases can cause the immune system to attack intestinal villi and microvilli.
Comparison Chart
Comparison Video
Conclusion
Cilia and microvilli are the finger-like projections present in the plasma membrane of some cells. The main difference between cilia and microvilli is that cilia are motile and take part in the movement of water and other substances, while microvilli are non-motile, and their main function is to increase the surface area of a cell on which they are present. Cilia are also involved in the rhythmic movement of some external objects like dirt, mucus, and microorganisms, which makes them helpful in cleaning the passageways. Microvilli, on the other hand, increase the absorption of nutrients in the intestine. Moreover, these both are different in their structure as well, as cilia are made up of microtubules arranged in longitudinal orientation while microvilli are composed of actin filaments held together by protein.
