Certified Neuroscience Registered Nurse (CNRN) Practice Exam

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

1. Absorption of nutrients

2. Digestion of fats

3. Storage of bile

4. Filtration of blood

The correct answer is: Absorption of nutrients

The jejunum primarily functions in the absorption of nutrients. This segment of the small intestine follows the duodenum and precedes the ileum. Its inner walls are lined with numerous villi and microvilli, which significantly increase the surface area and enhance the absorption of carbohydrates, proteins, vitamins, and mineral nutrients into the bloodstream. In terms of digestion, while the jejunum plays a role in the absorption of digested food, the initial digestion of fats occurs primarily in the duodenum with the aid of bile and pancreatic enzymes. The jejunum does not store bile; that function is performed by the gallbladder, which stores bile produced by the liver for the digestion of fats. Lastly, the filtration of blood is a function associated with the kidneys, not the small intestine. Thus, the jejunum’s primary role is indeed the absorption of nutrients, which is crucial for providing essential substances required for various bodily functions and growth.