Which section of the small intestine precedes the jejunum?

The section of the small intestine that precedes the jejunum is the duodenum. The small intestine is anatomically divided into three segments: the duodenum, jejunum, and ileum. The duodenum is the first part of the small intestine, directly connected to the stomach via the pyloric sphincter, and it plays a crucial role in the initial phases of digestion. It receives chyme from the stomach and digestive juices from the pancreas and liver, facilitating the breakdown of food.

Following the duodenum, the jejunum is the middle portion of the small intestine, which continues the process of digestion and nutrient absorption. The ileum then follows the jejunum and is primarily responsible for the absorption of vitamin B12 and bile salts, along with any remaining nutrients.

Understanding the sequence and function of these sections is essential for grasping how the digestive system is organized and operates. Knowledge of this anatomy is fundamental for health professionals in diagnosing and treating gastrointestinal issues.