Microvilli

Definition

Microvilli are small, finger-like projections that extend from the surface of epithelial cells, significantly increasing their surface area. These structures are particularly abundant in the intestines, where they enhance nutrient absorption by providing a larger area for interaction with digested food. Microvilli are crucial for efficient digestion and play a role in the overall functioning of the digestive system.

5 Must Know Facts For Your Next Test

1. Microvilli are composed of a core of actin filaments that help maintain their structure and support their function in absorption.
2. The brush border refers to the densely packed array of microvilli on the surface of intestinal epithelial cells, resembling a brush.
3. Each intestinal epithelial cell can have thousands of microvilli, greatly amplifying the absorptive capacity of the intestine.
4. Microvilli are involved not only in nutrient absorption but also in signaling processes and maintaining the barrier function of the intestinal lining.
5. Damage to microvilli can lead to malabsorption issues, contributing to various gastrointestinal disorders and nutrient deficiencies.

Review Questions

• How do microvilli enhance the absorption process in the digestive system?
  • Microvilli enhance absorption by dramatically increasing the surface area of epithelial cells in the intestines. This larger surface area allows for more efficient interaction with nutrients from digested food. The dense array of microvilli forms what is known as the brush border, which plays a crucial role in maximizing nutrient uptake into the bloodstream.
• What is the structural composition of microvilli and how does it contribute to their function?
  • Microvilli are made up of a core of actin filaments that provide structural support and maintain their shape. This unique structure allows them to extend outward from the cell surface, effectively increasing surface area without compromising stability. The actin filaments also play a role in facilitating cellular processes such as absorption and signaling, making microvilli integral to the functionality of epithelial cells.
• Evaluate the consequences of damage to microvilli in terms of digestive health and overall nutrition.
  • Damage to microvilli can have serious implications for digestive health by impairing nutrient absorption. When microvilli are damaged, as seen in conditions like celiac disease or inflammatory bowel disease, the absorptive capacity of the intestines is significantly reduced. This can lead to malabsorption syndromes, resulting in deficiencies in essential nutrients and overall poor health, highlighting their critical role in maintaining nutritional balance.

Related terms

Villi:

Villi are larger, finger-like projections found in the small intestine that also increase the surface area for absorption, working alongside microvilli.

Epithelial Cells: Epithelial cells form protective layers on surfaces and are responsible for absorption, secretion, and sensation in various organs, including the digestive system.

Absorption: Absorption is the process through which nutrients from digested food pass through the intestinal wall into the bloodstream, a function significantly enhanced by microvilli.