Anatomy and Physiology II Practice Test

What is the primary function of villi in the small intestine?

1. Secretion of mucus

2. Absorption of nutrients

3. Digestion of proteins

4. Storage of waste

The correct answer is: Absorption of nutrients

The primary function of villi in the small intestine is the absorption of nutrients. Villi are small, finger-like projections that increase the surface area of the intestinal lining, allowing for more efficient absorption of nutrients from digested food. Each villus is covered with even smaller hair-like structures called microvilli, which further enhance the absorptive capacity of the intestine. This specialized structure is crucial because the small intestine is the main site for nutrient absorption, and maximizing surface area is essential for the body to effectively extract vitamins, minerals, carbohydrates, proteins, and fats from the food we consume. The secretion of mucus, digestion of proteins, and storage of waste are important processes in the digestive system but are not the primary functions of the villi themselves. Mucus is secreted by goblet cells to lubricate and protect the intestinal lining, while protein digestion primarily occurs through enzymes produced in the stomach and pancreas. Waste storage is primarily the function of the large intestine, not the small intestine where the villi are located.