Frog
The food for the frog moves first through his mouth, where saliva breaks down the food particles. From there, the food goes down into the esophagus, and is pushed into a sac like structure stomach. Particles from the food are broken down when they are mixed with enzymes and other acidic fluids. When it is a little digested, the food moves through the intestines, where the majority of digestion occurs. The frog absorbs the key nutrients it gets from its food, and pancreatic juices are secreted through the gallbladder from the live to the small intestine. This process helps complete digestion. Wastes are passed through either the frog's urinary bladder, or are excreted through the cloaca, a slit that opens at the end of the digestive system.
African Lion
Iguanas
Iguanas are fascinating reptiles. They have extremely complex digestive systems. When an Iguana consumes food its mouth begins to become filled with saliva to help start the break down of the food and allow it to slip easily down its thought Iguanas have ridiculously sharp teeth to chew food into tiny pieces, and its fork-like tongue is used to push the food to the roof of its mouth until it is able to swallow. The food then goes through the pharynx, the tube that connects its throat to its esophagus, down the esophagus, and to the stomach where gastric juices are produced. A mix of stomach acid and enzymes break down the food. The lingering food particles continue toward the small intestine where release of its pancreatic juice filled with enzymes breaks down more of the food. This juice also negates the stomach acid because the intestine cannot cope with it.The Iguanas liver produces bile to break down fats in the small intestine. This bile is kept in the gallbladder until ready for release. The Hindgut of the Iguana then creates a process of fermentation by breaking down molecules the Iguana ate. This allows for energy extraction from the food. After this fermentation, the large Intestine is the last place where nutrition is absorbed. All solid remaining food particles turn into waste and are released through the anus.