Manometry also allows the doctor to examine the muscular valve connecting the esophagus with the stomach, called the lower esophageal sphincter, or LES.

The sphincter of Oddi is a muscular valve that controls the opening of the ampulla.

With gravity's help, a muscular valve called the lower esophageal sphincter, or LES, keeps stomach acid in the stomach.

These external openings, which act as muscular valves in some insects, lead to the internal respiratory system, a densely networked array of tubes called tracheae.

As food reaches the end of the esophagus, it enters the stomach through a muscular valve called the lower esophageal sphincter.

The pyloric sphincter is a muscular valve that opens to allow food to pass from the stomach to the small intestine.

The bladder sphincter is a muscular valve that lies at the bottom of the bladder.

Normally, a muscular valve called the lower esophageal sphincter (LES) opens to allow food into the stomach (or to permit belching); then it closes again.

The ears and nostrils of pygmy hippos have strong muscular valves to aid submerging underwater, and the skin physiology is dependent on the availability of water.

A muscular valve regulates the process of opening and closing the entrance of the lung.