Pyloric Sphincter

What is the pyloric sphincter?

Your pyloric sphincter is a band of muscle that acts as a valve between your stomach and small intestine. It opens to let small amounts of partially digested food (called chyme) flow from your stomach to your small intestine. Your pyloric sphincter makes sure digestion happens in a slow and controlled way, only letting chyme through at the right time and in the right amount. Because it lets just enough chyme in at a time, your small intestine can process and absorb the nutrients in your food.

What does the pyloric sphincter do?

Sphincters are ring-shaped muscles that control the flow of substances from one organ to the next. In the case of your pyloric sphincter, it controls the flow of substances from your pylorus (bottom part of your stomach) to your duodenum (the first section of your small intestine). It plays an important role in the digestive process.

You can think of your pyloric sphincter like a gate that opens and closes. When it relaxes (opens), it allows contents from your stomach to go to your small intestine. When it’s closed (contracted), it keeps digested food in your stomach until it’s ready to go to your small intestine. It’s an involuntary process, so you don’t have to consciously think about it.

One of the important features of your pyloric sphincter is that it controls the flow of digested food (chyme) so that your small intestine isn’t flooded with too much at once. Contractions and pressure from your stomach press onto your pyloric sphincter and cause it to open. Once it lets a small amount of chyme in, it closes again because it can sense that your small intestine is getting full. When it’s closed, it prevents contents from your small intestine from backflowing up into your stomach again.

Where is the pyloric sphincter?

Your pyloric sphincter is a muscle that separates the lowest part of your stomach from the uppermost part of your small intestine. It’s made of smooth muscle.

What happens when the pyloric sphincter doesn’t work?

Digestive problems can occur when your pyloric sphincter weakens or stops working. Factors like the acidity of your chyme and the signals it gets from your nervous system can affect how it works. It can naturally weaken or stop working due to trauma.

Some health conditions that involve problems with your pyloric sphincter are:

• Pyloric stenosis: The opening between your stomach and small intestine is thick and narrow, which prevents food from passing through. This condition mainly affects infants.
• Gastroparesis: Your pyloric sphincter doesn’t open as much as it should because your stomach muscles are weak and don’t push your food down. This leads to food sitting in your stomach too long.
• Bile reflux: Your pyloric sphincter is letting bile from your small intestine come back up into your stomach or esophagus.

Possible treatment for pyloric sphincter dysfunction could include:

• Surgery, like pyloroplasty, to widen the area just before your pyloric sphincter
• Medications to treat symptoms of bile reflux or stimulate your sphincter muscle
• Lifestyle changes like eating several small meals a day or foods high in fiber