Microvilli

Definition

Microvilli are tiny, finger-like projections that cover the apical surface of certain epithelial cells, such as those found in the small intestine. They function to increase the surface area of these cells, enhancing their ability to absorb nutrients and other substances from the surrounding environment.

5 Must Know Facts For Your Next Test

1. Microvilli increase the surface area of epithelial cells by up to 40 times, enhancing their ability to absorb nutrients, water, and other substances.
2. The high concentration of microvilli on the apical surface of intestinal epithelial cells is known as the brush border, which is essential for efficient nutrient absorption.
3. Microvilli contain actin filaments that provide structural support and allow for dynamic changes in their shape and size to optimize absorption.
4. Defects in the formation or function of microvilli can lead to various digestive disorders, such as celiac disease and microvillus inclusion disease.
5. The density and length of microvilli can be influenced by factors such as diet, age, and certain medications, which can impact nutrient absorption and overall digestive health.

Review Questions

• Explain the role of microvilli in the small intestine and their contribution to nutrient absorption.
  • Microvilli are the tiny, finger-like projections that cover the apical surface of intestinal epithelial cells, creating a brush-like appearance known as the brush border. The high concentration of microvilli significantly increases the surface area of these cells, allowing for more efficient absorption of nutrients, water, and other substances from the digestive tract. This increased surface area is crucial for the small intestine's ability to effectively absorb the essential nutrients required for the body's growth, maintenance, and overall health.
• Describe the structural features of microvilli and how they contribute to their function.
  • Microvilli are composed of actin filaments that provide structural support and allow for dynamic changes in their shape and size. This flexibility enables the microvilli to optimize their surface area and absorption capabilities in response to various factors, such as diet, age, and certain medications. The high density of microvilli on the apical surface of intestinal epithelial cells, known as the brush border, is essential for the small intestine's ability to efficiently absorb nutrients, water, and other substances required for the body's growth and maintenance.
• Analyze the potential impact of defects in microvilli formation or function on digestive health and nutrient absorption.
  • Defects in the formation or function of microvilli can lead to various digestive disorders, such as celiac disease and microvillus inclusion disease. In these conditions, the impaired structure or density of microvilli can significantly reduce the surface area available for nutrient absorption, leading to malabsorption and associated symptoms like diarrhea, weight loss, and nutrient deficiencies. Understanding the critical role of microvilli in facilitating efficient nutrient absorption is essential for recognizing and addressing these types of digestive disorders, as well as for maintaining overall digestive health and well-being.

Related terms

Brush Border: The dense array of microvilli that covers the apical surface of intestinal epithelial cells, creating a brush-like appearance that increases the surface area for absorption.

Absorption: The process by which nutrients, water, and other substances are taken up from the gastrointestinal tract and transported into the bloodstream or lymphatic system for distribution throughout the body.

Epithelial Cells: The cells that line the surfaces and cavities of the body, including the digestive, respiratory, and urinary systems, as well as the skin. They play a crucial role in absorption, secretion, and protection.