Final answer:
The narrowed distal region of the stomach is called the pylorus, which includes the pyloric antrum and pyloric canal leading into the duodenum, controlled by the pyloric sphincter.
Step-by-step explanation:
The narrowed distal region of the stomach is known as the pylorus. Specifically, this region includes the pyloric antrum, which is the wider part, and the pyloric canal, which is the narrower portion connecting to the duodenum. The pyloric sphincter is a band of smooth muscle at the junction between the stomach and the duodenum, which controls the emptying of the stomach contents into the small intestine.
The stomach is a crucial organ in the digestive system and has four main regions: the cardia, fundus, the body (which is the main part), and the pylorus. It is equipped with layers of smooth muscle that enable it to churn and mix food before it passes into the small intestine.