The pyloric sphincter regulates passage of chymefrom the stomach
The ring shaped muscle in the digestive system is the lower esophageal sphincter (LES).
the stomach
A rat's sphincter is a muscular ring that helps control the entry and exit of substances from its digestive system. It regulates the passage of food and waste materials through the digestive tract.
The gastrointestinal tract contains sphincters, which are circular muscles that regulate the movement of material through the digestive system. Some examples of sphincters in the gastrointestinal tract include the lower esophageal sphincter, pyloric sphincter, and anal sphincter.
The lower esophageal sphincter prevents stomach acid from flowing back up into the esophagus, helping to prevent heartburn and acid reflux.
If you are referring to the digestive system, I believe this would be the pyloric sphincter. After the stomach turns dry food into a wet mass, it delivers it to the duodenum via the pyloric sphincter (muscle).
The stomach precedes the small intestine in the digestive system. After food is chewed in the mouth and mixed with saliva, it travels down the esophagus and enters the stomach where further digestion and breakdown of food occurs before passing on to the small intestine for absorption of nutrients.
A sphincter muscle controls a circular opening in the body. It serves to regulate the passage of substances through the opening by contracting or relaxing. Examples include the anal sphincter and the sphincter muscles in the digestive system.
Bolus goes down esophagus, through lower esophageal sphincter (aka, cardiac sphincter) and into stomach. (A sphincter is a circular muscle which squeezes shut or opens the tubular digestive tract). It then passes through pyloric sphincter into small intestine. The small intestine is made up first of the duodenum, then jejunum, then ileum. From ileum, bolus goes to ascending colon, then transverse colon, then descending colon. From there to rectum and then out through anus (anal sphincter) .
If you're referring to sphincters "guarding" entrances and exits, it means that these specific muscles close the structure to prevent backflow of body fluid. Ex: there is a sphincter between the esophagus and the stomach that "guards" the entrance to prevent the very acidic gastric juice from entering the esophagus and damaging the lining. The muscles around the eye and mouth can also be considered sphincters.
The duodenum has a sphincter that controls the opening of the stomach to dump partially digested food into the small intestines. This sphincter can be weakened by stomach ulcers. After the duodenum, food stuffs continues through the small intestines where most digestion takes place.
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