Microvilli

Definition

Microvilli are tiny, finger-like projections that extend from the surface of epithelial cells, significantly increasing the surface area for absorption and secretion. These structures are particularly prominent in the small intestine, where they play a critical role in nutrient absorption, enhancing the efficiency of the digestive process.

5 Must Know Facts For Your Next Test

1. Microvilli are composed of a core of actin filaments that provide structural support and allow for flexibility in movement.
2. The dense layer of microvilli on the intestinal epithelial cells is often referred to as the 'brush border' due to its appearance under a microscope.
3. Each cell can have thousands of microvilli, greatly amplifying the cell's surface area and optimizing its ability to absorb nutrients.
4. Microvilli are also involved in signaling processes and can help transport specific molecules into the cell through specialized channels.
5. Damage to microvilli can lead to malabsorption syndromes, where nutrients are not properly absorbed, resulting in deficiencies and health issues.

Review Questions

• How do microvilli enhance the efficiency of nutrient absorption in the small intestine?
  • Microvilli increase the surface area of epithelial cells lining the small intestine, allowing for more contact with digested food. This larger surface area enables a greater number of nutrient transporters to be present, facilitating faster absorption rates. The close arrangement of microvilli also helps to create a more efficient environment for enzymatic activity and nutrient uptake.
• Discuss the structural composition of microvilli and its significance in their function.
  • Microvilli are primarily made up of actin filaments that provide structural support and allow for their movement. This composition is significant because it enables microvilli to maintain their shape while maximizing surface area. The flexibility provided by actin filaments allows microvilli to adapt to varying conditions within the intestinal lumen, optimizing nutrient absorption under different dietary scenarios.
• Evaluate the consequences of microvilli damage on overall digestive health and nutrient absorption.
  • Damage to microvilli can severely impact digestive health by reducing the surface area available for nutrient absorption. Conditions such as celiac disease or certain infections can lead to villous atrophy, diminishing the effectiveness of nutrient uptake. This impairment can result in malabsorption syndromes, leading to deficiencies in essential vitamins and minerals, weight loss, and various gastrointestinal symptoms, significantly affecting overall health and well-being.

Related terms

Villi:

Villi are larger, finger-like projections that line the inner surface of the small intestine, working alongside microvilli to increase surface area for nutrient absorption.

Epithelial Cells: Epithelial cells form a protective layer on body surfaces and line cavities and organs, playing essential roles in absorption, secretion, and sensation.

Absorption:

Absorption is the process by which nutrients from food are taken up into the bloodstream through the walls of the digestive tract, primarily occurring in the small intestine.