Which structure controls the flow of chyme from the stomach to the small intestine?

• A. Cardiac sphincter
• B. Lower esophageal sphincter
• C. Ileocecal valve
• D. Pyloric sphincter

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the function of the stomach and its role in digestion. The stomach is responsible for breaking down food into a semi-liquid substance called chyme, which is then passed to the small intestine for further digestion and nutrient absorption.
2. Step 2: Learn about the pyloric sphincter. This structure is a ring of smooth muscle located at the junction between the stomach and the duodenum (the first part of the small intestine). Its primary function is to regulate the flow of chyme from the stomach to the small intestine.
3. Step 3: Differentiate the pyloric sphincter from other structures mentioned in the problem. For example, the cardiac sphincter (also known as the lower esophageal sphincter) controls the flow of food from the esophagus into the stomach, while the ileocecal valve regulates the flow of material from the small intestine to the large intestine.
4. Step 4: Recognize that the pyloric sphincter opens and closes in response to signals from the nervous system and hormones, ensuring that chyme is released into the small intestine in controlled amounts to optimize digestion and prevent overloading.
5. Step 5: Confirm that the correct answer is the pyloric sphincter, as it is the specific structure responsible for controlling the flow of chyme from the stomach to the small intestine.