The Functions of the Small Intestine: Digestion, Absorption, and Nutrient Transport

The small intestine is a vital organ in the digestive system that plays a crucial role in the digestion, absorption, and transport of nutrients. It is a long, coiled tube located between the stomach and the large intestine. In this article, we will explore the functions of the small intestine in detail, highlighting its essential role in the digestive process and overall nutrient utilization.

1. Digestion

One of the primary functions of the small intestine is to continue the process of digestion that begins in the stomach. The small intestine receives partially digested food from the stomach, along with digestive enzymes and bile from the liver and gallbladder. The enzymes break down complex carbohydrates, proteins, and fats into smaller molecules that can be absorbed by the body. The small intestine also produces its own digestive enzymes, such as sucrase, lactase, and maltase, which help break down specific carbohydrates.

2. Absorption

The small intestine is responsible for the absorption of nutrients from the digested food into the bloodstream. The inner lining of the small intestine is covered in tiny finger-like projections called villi, which greatly increase the surface area available for absorption. The villi are further covered in microvilli, forming a brush border that enhances nutrient absorption. Through this intricate system, nutrients such as carbohydrates, proteins, fats, vitamins, and minerals are absorbed into the bloodstream and transported to various cells and tissues throughout the body.

3. Nutrient Transport

Once absorbed, the nutrients from the small intestine are transported to the liver via the bloodstream. The liver plays a vital role in processing and storing these nutrients. Carbohydrates are converted into glucose and stored as glycogen, while excess glucose is converted into fat for long-term storage. Proteins are broken down into amino acids, which are used for various cellular functions and protein synthesis. Fats are processed and packaged into lipoproteins for transport to different tissues. The small intestine, in coordination with the liver, ensures that nutrients are efficiently transported and utilized by the body.


The small intestine is a remarkable organ that performs essential functions in the digestive system. It continues the process of digestion, breaking down complex molecules into smaller ones. It absorbs nutrients from the digested food and transports them to the bloodstream for distribution throughout the body. Understanding the functions of the small intestine helps us appreciate the intricate mechanisms involved in nutrient digestion and utilization.

Thank you for reading this article on the functions of the small intestine. Take a moment to reflect on the incredible role that the small intestine plays in the digestion and absorption of nutrients, ultimately contributing to our overall health and well-being!