Leaving Certificate Digestion Practice Test

The main concept being tested is where mechanical digestion turns food into a semi-liquid form called chyme. In the stomach, the muscular walls contract strongly to churn and mix the food with gastric juices like acid and pepsin, transforming it into chyme. This churning is the mechanical part of digestion that prepares the contents for further processing in the small intestine. The other organs have different roles: the lungs handle breathing, the liver makes bile for fat digestion but doesn’t churn food, and the pancreas releases digestive enzymes but doesn’t perform the churning itself. So the organ responsible for turning food into chyme is the stomach.