Do Dogs and Cats Have the Same Digestive Tract?
Beyond the number of teeth—30 permanent teeth in cats versus 42 in dogs—and a few extra dozen centimeters in dogs, the anatomy of the digestive tract ultimately shows few differences between these two species.
What organs make up the digestive system?
Our four-legged companions' digestive system begins in the mouth—for cats—and the muzzle—for dogs. The oral cavity consists of the tongue, gums, teeth, and salivary glands, among other structures. It is followed by the pharynx, which enables swallowing. The stomach comes next, connected to a long tube called the esophagus. The food bolus—food ground in the oral cavity and mixed with saliva and gastric juices—then leaves the stomach through a valve called the pylorus. It next enters the first part of the small intestine: the duodenum. The second and third sections of this long tube (over a meter long in cats!) are called the jejunum and ileum. The small intestine is followed by the large intestine, also known as the colon. This organ first includes the cecum, then divides into three parts: the ascending, transverse, and descending colon, ending in the rectum. The final section of the digestive tract is the anus, surrounded by anal glands.
There are also accessory organs, such as the liver, gallbladder, and pancreas. The spleen, although located in the abdominal cavity, has no role in digestive processes.
What Are the Functions of the Digestive Organs?
When food is consumed, it is first crushed—very roughly—in the oral cavity, thanks to the tongue and teeth. Unlike ours, the saliva of our four-legged companions does not aid in the predigestion of food; it solely serves to lubricate it.
After being swallowed in the pharynx and passing through the esophagus, these foods remain in the stomach for a few hours, where they are churned and mixed with gastric juices—enzymes that aid in their digestion. The highly acidic pH in the stomach also plays a key role in this process.
After this passage through a pouch formed by layers of muscle, the gastric contents are gradually released into the small intestine. Along this entire tract, the digestive contents mix with intestinal fluid, are broken down into nutrients, and absorbed through the wall before entering the bloodstream. In the first section of this long tube—the duodenum—bile and pancreatic juice are secreted. The former is produced by the liver, stored in the gallbladder, and then released into the small intestine via the common bile duct. Bile aids in the breakdown of fats. Pancreatic juice, meanwhile, is produced by the exocrine portion of the pancreas. It helps regulate the pH of intestinal contents and digest proteins, sugars, and fats.
The large intestine, or colon, completes digestion and recovers waste products and water to form feces. It hosts a rich flora, also known as the microbiota.
Certain accessory organs of the digestive tract, such as the liver and pancreas, play a role in food digestion and nutrient absorption—but that’s not all! The liver, in addition to secreting bile, has functions:
- detoxifying: by breaking down medications, among others;
- cholesterol regulation;
- metabolite excretion: bilirubin results from hemoglobin breakdown;
Without forgetting its synthesis and storage roles.
The endocrine pancreas produces two hormones: insulin and glucagon, essential for regulating blood sugar levels.
The spleen, though considered an accessory organ, is not involved in digestion. It acts as a blood reservoir and plays a role in immunity, as well as in the renewal of blood cells.
