Stomach: Anatomy, Function, Diagram, Parts Of, Structure (2024)

Where is the stomach located?

Your stomach sits in your upper abdomen on the left side of your body. The top of your stomach connects to a valve called the esophageal sphincter (a muscle at the end of your esophagus). The bottom of your stomach connects to your small intestine.

How big is your stomach?

The size of the stomach varies from person to person. Your stomach expands when full and deflates when empty. Because of this, your stomach size can vary depending on how recently and how much you have eaten.

What are the parts of the stomach’s anatomy?

Your stomach has five distinct sections:

• The cardia is the top part of your stomach. It contains the cardiac sphincter, which prevents food from traveling back up your esophagus.
• The fundus is a rounded section next to the cardia. It's below your diaphragm (the dome-shaped muscle that helps you breathe).
• The body (corpus) is the largest section of your stomach. In the body, your stomach contracts and begins to mix food.
• The antrum lies below the body. It holds food until your stomach is ready to send it to your small intestine.
• The pylorus is the bottom part of your stomach. It includes the pyloric sphincter. This ring of tissue controls when and how your stomach contents move to your small intestine.

What is the stomach’s structure?

Several layers of muscle and other tissues make up your stomach:

• Mucosa is your stomach’s inner lining. When your stomach is empty, the mucosa has small ridges (rugae). When your stomach is full, the mucosa expands, and the ridges flatten.
• Submucosa contains connective tissue, blood vessels, lymph vessels (part of your lymphatic system) and nerve cells. It covers and protects the mucosa.
• Muscularis externa is the primary muscle of your stomach. It has three layers that contract and relax to break down food.
• Serosa is a layer of membrane that covers your stomach.