Final answer:
The obstructive narrowing of the pyloric sphincter is commonly known as pyloric stenosis, which can cause symptoms such as vomiting and dehydration.
Step-by-step explanation:
The obstructive narrowing of the pyloric sphincter is commonly known as pyloric stenosis. This condition is characterized by the thickening of the pyloric sphincter, which is the muscular valve that controls the passage of food from the stomach to the duodenum. Pyloric stenosis is an uncommon condition in infants that blocks food from entering the small intestine. Typically, a muscular valve between the stomach and small intestine holds food in the stomach until it is ready for the next stage in the digestive process. Pyloric stenosis can inhibit the normal process of gastric emptying, causing vomiting, dehydration, and an imbalance of electrolytes in the body.