Kaplan Nursing Entrance Practice Exam

Which part of the body is primarily responsible for nutrient absorption?

1. Stomach

2. Large intestine

3. Small intestine

4. Liver

The correct answer is: Small intestine

The small intestine plays a crucial role in nutrient absorption, making it the primary site in the digestive system for this process. It is specifically designed to maximize absorption through its extensive surface area, which is enhanced by finger-like projections called villi and microvilli. These structures increase the surface area available for nutrients to be absorbed into the bloodstream. As food travels through the small intestine, enzymes from the pancreas and bile from the liver further break down food contents, allowing nutrients such as carbohydrates, proteins, and fats to be absorbed effectively. Each section of the small intestine—duodenum, jejunum, and ileum—has a specific role, but it's primarily in the jejunum and ileum where the majority of nutrient absorption occurs. While other parts of the digestive system contribute to digestion and absorption processes, they do not primarily handle nutrient absorption to the same extent as the small intestine. The stomach primarily aids in digestion through the breakdown of food with gastric acids, while the large intestine mainly absorbs water and electrolytes and processes waste. The liver's role is vital in metabolic processes and detoxification, but it is not directly involved in absorbing nutrients from food.