Microvilli

Definition

Microvilli are tiny, finger-like projections found on the surface of epithelial cells, especially in the intestines. These structures significantly increase the surface area available for absorption and secretion, playing a critical role in nutrient uptake and overall digestive efficiency.

5 Must Know Facts For Your Next Test

1. Microvilli are often referred to as the 'brush border' due to their dense arrangement on epithelial cells, particularly in the small intestine.
2. Each microvillus contains a core of actin filaments, which help maintain its structure and support its function.
3. The increased surface area provided by microvilli is crucial for enhancing nutrient absorption, allowing for efficient uptake of carbohydrates, proteins, and fats.
4. Microvilli also contain enzymes and transport proteins that aid in the digestion of food and facilitate the movement of nutrients into the cells.
5. Damage to microvilli can lead to malabsorption disorders, resulting in nutritional deficiencies and gastrointestinal issues.

Review Questions

• How do microvilli contribute to the efficiency of nutrient absorption in the intestines?
  • Microvilli significantly increase the surface area of epithelial cells in the intestines, which allows for more effective absorption of nutrients. The larger surface area means that more contact can occur between nutrients and the intestinal lining. Additionally, microvilli contain enzymes that aid in digestion and transport proteins that facilitate the uptake of essential nutrients into the cells.
• Discuss how damage to microvilli can affect overall digestive health.
  • Damage to microvilli can lead to decreased surface area for absorption, which negatively impacts nutrient uptake and can result in malabsorption disorders. This may cause symptoms like diarrhea, weight loss, and deficiencies in essential vitamins and minerals. The health of microvilli is crucial for maintaining proper digestive function and overall nutritional status.
• Evaluate the role of microvilli compared to other structures like villi in enhancing intestinal absorption.
  • Microvilli play a complementary role to villi in enhancing intestinal absorption. While villi are larger projections that increase surface area on a broader scale, microvilli provide an additional level of surface area at a microscopic level. This two-tiered system maximizes absorption efficiency; villi capture larger amounts of nutrients from digested food, while microvilli fine-tune this process by facilitating immediate contact with nutrient molecules and enzymatic action for further breakdown.

Related terms

Villi:

Villi are larger, hair-like structures that also increase the surface area of the intestinal lining, aiding in nutrient absorption.

Epithelial Cells: Epithelial cells are thin layers of cells that line the surfaces of organs and structures throughout the body, including the intestines.

Absorption: Absorption is the process by which nutrients from food are taken up into the body through the intestinal wall.