Microvilli and villi in parts of the small intestine serve what main function?

The primary function of microvilli and villi in the small intestine is to increase the surface area for absorption. The small intestine is crucial for nutrient absorption, and having a larger surface area allows for more efficient absorption of nutrients into the bloodstream. Villi are small, finger-like projections that extend from the lining of the intestine, while microvilli are even smaller projections that cover each villus. This arrangement maximizes the intestinal surface area in a compact space, making nutrient absorption much more effective.

When food is digested, it passes through the small intestine where these structures work together to absorb essential nutrients such as vitamins, minerals, carbohydrates, proteins, and fats. Without this increased surface area, the ability to absorb sufficient nutrients from food would be significantly compromised.