The digestive system of the cat is a lot like ours. After all, we’re both mammals, and our organ structures are very similar. But there are some crucial differences because the cat evolved to be an obligate carnivore, while we humans can eat pretty much anything we want. Take a trip with me through your cat’s digestive system and find out what makes your cat tick.
Typically a cat swallows her food in chunks rather than chewing: cat teeth don’t have flat chewing surfaces like ours, and cat jaws only move up and down, while ours can move from side to side to aid in the chewing of vegetables and other such material. The tongue positions the food for shredding and tearing and mixes it with saliva to start the breakdown of carbohydrates.
After the tongue pushes the food toward the throat, the muscles in this 12- to 15-inch-long tube move it down to the stomach.
From the esophagus, the food passes through a sphincter (a ring of muscles) into the stomach itself. Here, acid begins the serious breakdown of food, particularly proteins. A cat’s stomach acid is strong enough to dissolve bones. The contractions of the stomach mix and grind food with secretions, turning it into a liquid before it passes to the next stage of digestion.
From the stomach, the food slurry passes through another sphincter into the duodenum, the first part of the small intestine. Here, two things happen: the gall bladder releases bile and the pancreas releases several enzymes.
Bile, a chemical produced by the liver and stored in the gall bladder, breaks up large fat molecules into smaller ones that can be absorbed in the next stage of the digestive process. The enzymes secreted by the pancreas (which unfortunately does not appear in the illustration above) neutralize the acids in the food slurry before the mixture passes into the intestine, and aid in digestion of sugar, fat and protein. The best known of these is insulin, which regulates the levels of glucose in your cat’s body.
The small intestine is the longest part of the cat’s digestive system. All nutrients are absorbed there: the small intestine is lined with tiny bodies called villi, which absorb proteins, enzymes, electrolytes and water.
In the large intestine, also known as the colon, the last available water and electrolytes are absorbed from the food. Solid feces form and beneficial bacteria produce enzymes that break down material that is more difficult to digest.
Here, the formed feces collect until they’re ready to be ejected into the litter box. The transit time from mouth to anus is about 20 hours.
So, why does your cat go to the bathroom shortly after he eats? When food reaches the stomach and the digestive process begins, an "eject your cargo" signal is sent to the colon. This is called the gastrocolic reflex, and it’s why cats (and people) feel the urge to poop after they eat.
Do you have any other questions about the feline digestive system? Are there digestive disorders or conditions that you’d like me to explore? Ask away in the comments.
About JaneA Kelley: Punk-rock cat mom, science nerd, animal shelter volunteer, and all-around geek with a passion for bad puns, intelligent conversation, and role-play adventure games. She gratefully and gracefully accepts her status as chief cat slave for her family of feline bloggers, who have been writing their cat advice column, Paws and Effect, since 2003. JaneA dreams of making a great living out of her love for cats.