Digestive system

The digestive system is made of the alimentary canal and the digestive glands.

The alimentary canal is short because the frog is a carnivore, so the length of the intestine is reduced.

The path of food: mouth → buccal cavity → pharynx → oesophagus (a short tube) → stomach → intestine → rectum → cloaca, which opens to the outside.

Food is caught with the bilobed tongue.

In the stomach, HCl and gastric juices secreted by the stomach wall act on the food. The partly digested food, chyme, passes to the duodenum, the first part of the small intestine.

The liver secretes bile, which is stored in the gall bladder. The pancreas produces pancreatic juice containing digestive enzymes.

Bile and pancreatic juice reach the duodenum through a common bile duct. Bile breaks fat into fine droplets (emulsification), and pancreatic juice acts on carbohydrates and proteins; digestion is completed in the intestine.

Digested food is absorbed by numerous finger-like folds of the inner intestinal wall, the villi and microvilli. Undigested solid waste passes into the rectum and out through the cloaca.