Question: 150 Once the undigested and unabsorbed substances enter the caecum, their backflow is prevented by-
(1) Gastro – oesophageal sphincter
(2) Pyloric sphincter
(3) Sphincter of Oddi
(4) Ileo – caecal valve
Answer: Option (4)
Explanation:
The ileo-caecal valve is present between the ileum of the small intestine and the caecum of the large intestine.
Its main function is to regulate the passage of undigested and unabsorbed food material from the ileum into the caecum.
This valve also prevents the backflow of contents from the caecum into the ileum.
The gastro-oesophageal sphincter prevents reflux of food from stomach to oesophagus.
The pyloric sphincter controls the passage of food from stomach to duodenum.
The sphincter of Oddi regulates the flow of bile and pancreatic juice into the duodenum.
Therefore, backflow from the caecum is prevented by the ileo-caecal valve.