What part of the stomach joins small intestine?

The part of the stomach that joins the small intestine is called the pylorus. The pylorus is a muscular sphincter that controls the passage of food from the stomach into the duodenum, the first part of the small intestine.

When food is ready to be emptied from the stomach, the pyloric sphincter relaxes and opens, allowing the food to pass into the duodenum. The pyloric sphincter also helps to prevent the reflux of food and stomach acid back into the stomach.