How is a dog's stomach structured? - briefly
A dog's stomach is divided into four main regions: the cardia, fundus, body (or corpus), and pylorus. The stomach wall consists of four layers: the serosa, subserosa, muscularis externa, and mucosa, which facilitates digestion and nutrient absorption.
How is a dog's stomach structured? - in detail
The canine stomach, much like that of humans, plays a crucial role in the digestive process. It is located in the upper abdomen, cranial to the small intestine and caudal to the esophagus. In terms of structure, the dog's stomach is divided into four main regions: the fundus, the body (corpus), the antrum, and the pyloric part.
The fundus is the upper part of the stomach where food initially enters. It serves as a reservoir for undigested food, allowing the dog to eat relatively large meals quickly without immediate digestion. The fundus has a capacity to expand significantly, accommodating up to 70% of the total stomach volume.
The body or corpus is the main part of the stomach and is responsible for the majority of chemical digestion. It contains numerous gastric glands that secrete hydrochloric acid (HCl), pepsinogen, and intrinsic factor. Hydrochloric acid helps to break down food and create an acidic environment necessary for pepsin activation. Pepsinogen is converted into the active enzyme pepsin, which aids in protein digestion. Intrinsic factor is crucial for vitamin B12 absorption in the small intestine.
The antrum is the lower part of the stomach that connects to the duodenum through the pyloric sphincter. It functions primarily as a mixing chamber, where peristaltic movements help to churn food into a semi-liquid mixture called chyme. The antrum also houses additional gastric glands that secrete gastrin, a hormone that stimulates the production of HCl and pepsinogen in the body of the stomach.
The pyloric part is the narrow segment that leads directly to the duodenum. It contains the pyloric sphincter, which regulates the passage of chyme into the small intestine. The sphincter ensures that only sufficiently digested food enters the intestines, preventing undigested material from passing through too quickly.
Overall, the dog's stomach is a highly specialized organ designed to efficiently process and digest a wide variety of foods. Its structure allows for both mechanical and chemical breakdown of ingested materials, facilitating the absorption of nutrients in the subsequent stages of the digestive system.