Ingestion and Digestion

The cat's teeth tear meat like serrated blades, and the barbed tongue scrapes it from bones. Saliva lubricates and binds food for swallowing.

Food passes down the esophagus and into the stomach. The top of the stomach, the fundus, produces acid to break down fibers, and an enzyme to break down protein.

The secretion of these digestive "juices" is hormonally controlled. The stomach also secretes mucus to protect it and the intestines against damage from the juices.

Muscle contractions mix food, which then passes into the duodenum.

The duodenum receives fat-dissolving bile from the gallbladder in the liver and enzymes from the pancreas.

Along the length of the small intestine, which is made up of the duodenum and ileum, digestion continues and nutrients are absorbed through the intestinal wall.

The blood carries these products to the liver, the largest internal organ. The liver processes them into essential fatty acids and amino acids, the "building blocks of life."

Unlike the human or canine liver, the feline liver needs animal protein to manufacture the full complement of acids, so a cat will die if it does not eat meat. The liver also breaks down toxic substances.