Certified Surgical Technologist (CST) Practice Exam

What is the primary function of the small intestine?

1. Synthesis of vitamins

2. Production of bacteria

3. Excretion of bile

4. Absorption of nutrients

The correct answer is: Absorption of nutrients

The primary function of the small intestine is the absorption of nutrients. This vital process takes place after the food has been digested in the stomach. The small intestine consists of three segments: the duodenum, jejunum, and ileum, each playing a role in digestion and absorption. In the duodenum, digestive enzymes from the pancreas and bile from the liver further break down the food, making nutrients available for absorption. Following this stage, the jejunum and ileum are primarily responsible for absorbing these nutrients, including carbohydrates, proteins, fats, vitamins, and minerals, into the bloodstream. The large surface area of the small intestine, due to its villi and microvilli, enhances its capacity to absorb nutrients efficiently. While the synthesis of vitamins, production of bacteria, and excretion of bile play roles in the overall digestive system’s function, they do not represent the main purpose of the small intestine itself. The focus remains on nutrient absorption, which is critical for providing energy and essential components to the body.