What regulates the opening of oesophagus into the stomach?
1. A membranous valve
2. A muscular sphincter
3. A mesodermal septum
4. A cartilaginous flap
The opening of the stomach into the duodenum is guarded by:
1. Cardiac sphincter
2. Sphincter of Oddi
3. Pyloric sphincter
4. Ileocaecal sphincter