Stomach

Your stomach is a hollow, J-shaped organ that begins to digest the food you eat. It makes enzymes and acids. Together, these chemicals break down food so it can pass into your small intestine.

Your stomach is part of your gastrointestinal (GI) tract. This is a long, muscular tube that starts at your mouth and goes all the way down to your anus (butthole), where poop (stool) leaves your body. The GI tract is an important part of your digestive system, and your stomach helps kickstart the digestive process.

What does your stomach do?

Your stomach digests food. To do this, it:

• Temporarily stores the food
• Squeezes and relaxes to mix the food and break it down
• Makes enzymes, acids and special cells that help with digestion

When food mixes with the fluids that help break it down, it’s called chyme. After that, your stomach sends the chyme to your small intestine.

Where is your stomach located?

Your stomach is in your upper abdomen (belly), on the left side of your body.

The top of your stomach connects to a valve at the end of your esophagus (lower esophageal sphincter). This valve keeps stomach acids from traveling up into your esophagus or throat.

The bottom of your stomach connects to the duodenum, which is the first part of your small intestine. There, chyme continues to break down into nutrients your body can use.

What are the parts of your stomach?

Your stomach has four sections:

• Cardia: This is the top part of your stomach. It releases mucus that protects your stomach lining from digestive juices.
• Fundus: This is a rounded section next to the cardia. It’s where your body stores air that collects when you swallow. It also releases digestive juices.
• Body (corpus): This is the largest section of your stomach. It’s where your stomach contracts to start mixing food.
• Antrum: This is the bottom section of your stomach. It includes the pyloric antrum, pyloric canal and pyloric sphincter. Together, these parts store food and then move it into your small intestine.

Several layers of muscle and other tissues make up your stomach wall. These include the:

• Mucosa: This is your stomach’s inner lining. It has small ridges (rugae) that allow it to expand when you eat. It also has glands that make digestive juices.
• Submucosa: This layer has connective tissue, blood and lymph vessels, and nerve cells. It covers and protects the mucosa.
• Muscularis externa: This is the primary muscle of your stomach. It has three layers that squeeze and relax to break down food.
• Serosa: This is the outer layer that covers your stomach.

What does your stomach look like?

Your stomach is shaped like the letter “J” with a rounded top and bottom. It’s connected to two tubelike organs — the esophagus (connects at the cardia) and the duodenum (connects at the antrum). Stomach size varies from person to person and by how much you’ve eaten.

What are the common conditions and disorders that affect your stomach?

Some GI diseases can make it harder for your stomach to do its job. For example, they can inflame the stomach’s lining or keep it from moving and mixing food. Common conditions include:

• Gastric ulcers
• Gastritis
• Gastroesophageal reflux disease (GERD)
• Gastroparesis
• Indigestion (dyspepsia)
• Peptic ulcer disease
• Stomach cancer

You can also have GI symptoms under specific circumstances. For example, you might have acid reflux after eating spicy foods or develop heartburn during pregnancy.

How do I know if something is wrong with my stomach?

If you experience any of these symptoms often, reach out to a healthcare provider:

• Constipation or diarrhea
• Loss of appetite
• Unintended weight loss
• Bloating
• Stomach pain
• Heartburn

Seek immediate medical attention if you have:

• Chest pain
• Fever
• Nausea and vomiting
• Pus or blood in your poop
• Severe dehydration or diarrhea
• Sudden and intense belly pain