You may not pay much attention to your dog's stomach other than when your dog brings food back up from there or when you watch him wolf down food like if there was no tomorrow, but your dog's stomach is sure a fascinating body part. We often take a dog's stomach for granted when it's often doing loads of work, from storing food to preparing it for its further journey down the lower digestive tract. So today's spot of honor is dedicated to Rover's stomach, so let's listen to what our dog's stomach has to say!
Introducing the Dog's Stomach
Hello, it's your dog's stomach talking! Ever wondered where that whole bowl of food your dog ate goes? In his stomach of course! You see, when your dog eats food, it travels from his mouth down to the esophagus where it then reaches a valve-like structure that's known as the cardiac sphincter or antrum cardiacum.
Just like a valve, this muscular sphincter opens and closes as needed. In between meals, the valve is closed, but when your dog eats or drinks, the valve opens so to allow food and water to reach me.
Once the food reaches me, the valve closes again, but it can sometimes be forcefully opened when I am full of air (as it often happens when your dog eats too fast!) and the air pressure forces the valve to open causing your dog to burp. When food makes it past the cardiac sphincter, it finally reaches me and then it's my turn to go to work!
I am Storage Unit
I am a sac-like structure located between the esophagus and duodenum (small intestine) and one of my main goals is to store your dog's food.
When your dog eats, I tend to distend and act as a reservoir, but I am also contracting in the meanwhile so to help mix up and churn the food.
As food is ground up, the parts that are mostly liquefied (chyme) are sent to the duodenum for further digestion, while the larger parts remain inside me awaiting to become a more liquid form.
This explains why liquid medications are more readily absorbed compared to solid or semisolid foods.
Did you know? According to veterinarian Race Foster, once ingested, most food leaves the dog's stomach within twelve hours.
I Aid in Digestion
My interior surface is lined up with several folds known as "gastric folds." These folds are responsible for grinding up the food your dog wolfs down for breakfast and dinner. On top of that, I secrete acids and enzymes to help break down the food further. The acid I produce is known as hydrochloric acid and it's very strong! It is thanks to this acid that your dog can digest things that you may not be able to. You would think this acid I produce would harm me, but thankfully, I have a protective lining of mucus that prevents me from auto-digesting myself.
Once I have started the preliminary digestive process, the partially digested food can then be sent to the duodenum (where the main part of the digestion occurs) through the pyloric sphincter. Like the cardiac sphincter, the pyloric sphincter acts as a valve, opening and closing to regulate the flow of food that reaches the duodenum.
When Things Go Wrong
Despite being a simple storage sac that can grind up food and initiate the digestive process, many things can go wrong with me. I can get irritated and inflamed, I may produce too much acid, my protective layers may be affected and I can develop growths and dangerous cancers. On top of that, dogs can swallow things that are unable to pass through me, leading to debilitating blockages.
Gastritis comes from the ancient Greek word gastḗr, meaning “belly” and itis meaning inflammation. There are many things that can cause me to get inflamed. As in humans, viruses and bacteria, ingestion of spoiled food, abrupt dietary changes, certain medications and overeating can irritate me and cause a bout of gastritis. Affected dogs will be vomiting, refuse food and act lethargic. While in several instances the issue is short term and I recover after being fasted (yes, I too benefit from some rest at times!) and offered a dog upset stomach bland diet, repeated episodes of vomiting are often a red flag that there's some underlying problem that needs addressed.
Presence of Ulcers
As discussed above, when a dog's cardiac sphincter works well, the valve opens when food and water needs to reach me and then remains in the closed position at other times. However, sometimes the valve can weaken or become damaged, and when this happens, it doesn't open and close as it should causing some of my acid to seep through and reach the esophagus, causing an esophagitis (yes, now it's his turn to get irritated.)
While as mentioned I have a protective layer of mucus that prevents me from digesting myself, sometimes when I produce too much acid or my local protective force weakens, or both, the acid I produce may manage to harm me, predisposing me to ulcers. What can cause me to produce too much acid or weaken my protective mucosa? Certain conditions such as mast cell tumors, stress or the administration of anti inflammatories, pain killers and corticosteroids, just to name a few. Affected dogs will typically vomit, lose their appetite and there may be fresh of digested blood in it.
As with the cardiac sphincter, the pyloric sphincter may also malfunction. In this case, after undergoing repeated muscle spasms its passage may become narrow, triggering what is known as pyloric stenosis. This condition is more common in small nervous dogs in which it may cause them to occasionally regurgitate partially digested food within two hours of eating. In severe cases, dogs may regurgitate more often leading to weight loss.
Bloat and Torsion
Perhaps, one of the problems I am mostly associated with is bloat which most commonly affects large dogs with deep chests. When I fill up too much with air, I tend to dilate and if I fill up too much, I risk twisting on my axis leading to a potentially life threatening torsion that can cause shock and death if not treated immediately. Affected dogs develop a swollen belly, they may be dry heaving, retching and pacing anxiously. This is a medical emergency!
Dogs can eat the strangest things, and sometimes foreign bodies such as balls, buttons or bones can get lodged somewhere in the gastro-intestinal tract. When something gets stuck inside me, it's important to take prompt action as foreign bodies can cause me lacerations, erosions and even perforations. When help is sought quickly, vets may retrieve the ingested object through endoscopy, via a tube inserted in the dog's esophagus with attachments that reach me and allow the foreign item to be grasped. If this option isn't feasible, the foreign object may need to be removed surgically.
Sadly, I can also get cancer. According to veterinarian Dr. Rance K. Sellon, the most common stomach tumor affecting dogs is adenocarcinoma, followed by lymphosarcoma and smooth muscle tumors (leiomyomas, leiomyosarcomas). Usually, stomach cancer happens mostly in middle-aged to older dogs that present with chronic vomiting, loss of appetite and weight loss. Like in the case of a blockage, the tumor may grow so big that food cannot pass through me so it's vomited back up, which leads to weight loss as the dog is no longer able to receive food as it should.
The above are just a few of the many things that can go wrong with me. I hope this article has helped you understand me better. As you have seen, I do quite a whole lot! If you wish, you can compare my workload to a washing machine, where food is loaded up, rinsed with acids and enzymes and then tumbled out to the intestinal tract. You may want to keep me in good shape so that I don't make your dog sick and lose his appetite! Keep an eagle eye on your dog to ensure he doesn't ingest things that he shouldn't, feed him a easily digestible diet and report to your vet promptly if something seems amiss. Me and your dog will thank you!
Your dog's stomach.
Disclaimer: this article is not meant to be used as a substitute for professional veterinary advice. If your dog has a stomach problem, please see your vet promptly.
- Pet Education, Pyloric Stenosis, By Race Foster, retrieved from the web on April 25th, 2016
- DVM 360, Gastric ulcer disease in dogs and cats (Proceedings), by Rance K. Sellon, DVM, PhD, DACVIM, retrieved from the web on April 25th, 2016
- DVM360, Gastric neoplasms in dogs and cats (Proceedings) by Rance K. Sellon, DVM, PhD, DACVIM, retrieved from the web on April 25th, 2016
- Pet Education, Gastritis and Stomach Inflammation in Dogs, by Race Foster, retrieved from the web on April 25th, 2016
- Outline of stomach, showing its anatomical landmarks.Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See "Book" section below) Bartleby.com: Gray's Anatomy, Plate 1046 This is a retouched picture, which means that it has been digitally altered from its original version. Modifications: vectorization (CorelDraw). The original can be viewed here: Gray1046.png. Modifications made by Mysid. Public domain.