What is the first part of the small intestine that connects the stomach to the jejunum?

The part of the small intestine that connects the stomach to the jejunum is the duodenum. It serves as the initial section of the small intestine, following the pyloric sphincter of the stomach. The duodenum plays a crucial role in the digestive process by receiving partially digested food, called chyme, from the stomach. This section of the small intestine is also where digestive juices from the pancreas and bile from the liver enter the digestive process, further breaking down the food for nutrient absorption.

The jejunum follows the duodenum and is primarily involved in the absorption of nutrients, while the ileum is the final section of the small intestine that also absorbs nutrients, particularly vitamin B12 and bile salts. The pylorus, on the other hand, is the opening between the stomach and the duodenum, not a part of the intestine itself. Thus, the correct choice highlights the structure that serves as the immediate transition from the stomach to the next part of the digestive tract.