You may also have diarrhea or a fever. It is sometimes called stomach flu, but it is not the flu. Germs like viruses and bacteria can cause it. You can catch it from someone else who has it, or you can get it from food poisoning. Food poisoning can happen if you eat foods that contain harmful germs.
The circular muscle located at the entrance and exit to the stomach is called the sphincter. So for this question, you are talking about two distinct sphincters. This anatomical structure is able to open, and contract or close as needed.
What is the function of the rectus femoris muscle? Rectus abdominus is the large abdominal muscle in the center of the abdominal region. It controls pelvic tilt. The internal and external obliques are the abdominal muscles located adjacent to the rectus abdominus. The internal oblique stretches from the front of the abdomen to the back of the torso and aids in performing certain body functions such as breathing.