What is contained within the microvilli?

Microvilli are microscopic projections that extend from the surface of epithelial cells, especially those lining the intestines, and serve to increase the surface area for absorption. They contain a brush border of enzymes crucial for digestion, such as disaccharidases, peptidases, and other digestive enzymes that facilitate the breakdown of nutrients into absorbable units. This enhancement of surface area and presence of enzymes is vital for efficient nutrient uptake during the digestive process.

While hormones, nutrients, and bile salts are important components in digestion and absorption, they are not contained within the microvilli themselves. Hormones are secreted into the bloodstream, nutrients are absorbed into the bloodstream after digestion, and bile salts primarily assist in the emulsification of fats in the small intestine but are not located in the microvilli structure. The primary function of microvilli is to house digestive enzymes that act on substrates present in the intestinal lumen, confirming why the presence of digestive enzymes is the correct answer.