The cardia of the stomach is the region just below the Z-line at the LES. See the image link below for an image of the Z-line, LES and cardia of the stomach.
Both the upper and lower ends of the stomach have a sphincter that regulates flow into and out of the stomach. The lower esophageal sphincter is at the top of the stomach, and the pyloric sphincter is at the lower end of the stomach.
cardiac sphincter; or gastroesophageal sphincter; or lower esophageal sphincter (LES); or esophageal sphincter from http://en.wikipedia.org/wiki/Cardia
LES - Lower Esophageal Sphincter
The lower esophageal sphincter guards the entrance of the stomach from the esophagus.
Sphincters are circumferential muscles that can relax or constrict to regulate the passage of material through a particular area. The stomach is bound by two sphincters in humans: the lower esophageal sphincter that keep stomach acid in the stomach and the pyloric sphincter that regulates the flow of food in the stomach into the duodenum.
The name of the sphincter between the esophagus and the stomach is called the LES, or lower esophageal sphincter.
lower esophageal sphincter
Lower Esophageal Sphincter
The lower esophageal sphincter muscle/the cardiac sphincter muscle.
lower esophageal sphincter or gastroesophageal sphincter
The Lower Esophageal Sphincter.
at the junction of the esophagus and stomachlower-esophageal-sphincter