Is the duodenum part of the small intestine?

The duodenum is a part of the small intestine located between the stomach and the jejunum. It is approximately 25 cm in length and forms a "C" shape around the head of the pancreas. It is the shortest, widest, deepest, and most fixed portion of the small intestine. The primary function of the duodenum is to receive secretions from the stomach, pancreas, and liver (bile), making it an important site for digestion and absorption in the small intestine. At the same time, the duodenum is a relatively vulnerable part of the digestive tract and is prone to inflammation or ulcers caused by various factors such as food, medications, and alcohol. Therefore, it is important to maintain healthy dietary and lifestyle habits, avoid excessive alcohol consumption, and refrain from the misuse of medications.