What Does the Stomach Do? Its Anatomy and Functions
Pamela Cagle
What does the stomach do? From digestion to immune system support, learn about the stomachâs big role in your daily health.
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The term âstomachâ is often overused. You might say you have butterflies in your stomach when you feel nervous, complain of having a âstomachache,â or strive for a physique with a âflat stomach.â However, these sensations or characteristics have little to do with the organ. So what does the stomach do, really?

Your stomach is part of the digestive system, helping you turn food into energy and start the process of disposing of waste. Itâs a âj-shapedâ or âcomma-shapedâ organ inside your abdomen's left upper quadrant, and the size and shape of your stomach will vary based on factors like sex, body size, and how much food youâve recently eaten. In this article, weâll answer the question, âWhat does the stomach do?â including its anatomy, main functions, and how it communicates when something is wrong.

The Stomach Misconception

Itâs common to use the term âstomachâ when referring to your abdominal cavity. However, this region contains several vital organs, including the stomach, intestines, liver, and kidneys. You may call abdominal discomfort a âstomachacheâ or attribute feelings of nervousness or excitement to the organ. In actuality, those feelings and sensations stem from a complex interplay between nerves and hormones throughout the body.

What Does the Stomach Do? Its Anatomy

Your stomach is composed of soft tissue structures like muscles, nerves, and mucosa that help support digestion.Â

Cardia: The top part of your stomach which connects to the esophagus

Fundus: The dome-shaped, often gas-filled portion to the upper left of the cardia

Body: The central portion of your stomach

Antrum: The lower portion that holds the food you eat

Pylorus: The bottom portion that connects your stomach to your duodenum and small intestines

The five parts of the stomach wall include the following:

Mucosa: The innermost layer, which contains glands that produce digestive juices

Submucosa: The second layer, which supports the mucosa and contains rugae (gastric folds), blood vessels, lymphatic vessels, and nerves

Muscularis: The third layer, which is made of thick muscles that help mix food with digestive juices

Subserosa: Contains supporting tissues for the serosa

Serosa: The outermost layer, which wraps around the stomach to confine it

The Digestive Functions of Your Stomach

Your stomachâs anatomy creates an environment where food can be turned into nutrition using gastric acids and enzymes. The contents of your stomach help digest food by changing its pH and breaking it down. A typical adult human stomach will make about 1.5 liters of gastric secretions daily.

Gastric enzymes help food digest by splitting it into smaller molecules called chyme. Gastric acids, or gastric juices, are produced by the stomach's mucosal layer and are a combination of lipase, pepsin, and hydrochloric acid (HCL). The stomach also produces hormones like ghrelin, which signals hunger to the brain and communicates a sense of fullness after a meal. In all, your stomach plays a vital role in the digestive process and serves several essential functions, including:

Storage: The stomach's expandable shape acts as a temporary reservoir, holding food while initial digestive processes begin. The pyloric sphincter, at the bottom of the stomach, regulates the release of partially digested food (chyme) into the duodenum (the first part of the small intestine). This ensures a steady supply of nutrients without overwhelming the rest of the digestive tract.

Protein digestion: Gastric juices start breaking down proteins into smaller chains, preparing them for further digestion and absorption further down in the digestive tract.

Mixing and churning: The stomach muscles contract and relax, mixing food with digestive juices and breaking it down into smaller particles.

Digestive process: The stomach secretes gastric juices containing hydrochloric acid and enzymes like pepsin and gastrin, which start chemical digestion that begins the breakdown of proteins.

Absorption: The stomach absorbs nutrients, such as water, alcohol, and certain medications.

Emptying: The stomach empties the contents of the stomach into the small intestine through peristalsis.

What Does the Stomach Do Beyond Digestion?

While the stomach directly facilitates the following functions, itâs important to remember that it's part of a more extensive system. Other digestive organs like the pancreas, liver, and gallbladder function with the stomach to secrete digestive enzymes and bile, breaking down carbohydrates, fats, and proteins. Everything moves through the small intestine (duodenum, jejunum, and ileum), the large intestine, and eventually out as a bowel movement. But there are other functions beyond digestion that your stomach takes care of.

Bacteria elimination: Your stomach is an important part of the immune system. The stomach's highly acidic environment eliminates many harmful bacteria that may have entered with food, maintaining a healthy balance within the gastrointestinal tract.

Intrinsic factor production: The stomach produces intrinsic factor, a protein essential for absorbing vitamin B-12 in the small intestine. B-12 creates healthy blood cells and ensures proper nervous system function.

What to Do About Digestive Discomfort

Persistent digestive issues like heartburn, reflux, or unexplained stomachaches may significantly impact your quality of life. Occasional discomfort is normal, but frequent issues could indicate a more serious problem, such as:

Heartburn and reflux: A weakened lower esophageal sphincter allows stomach acid to rise, leading to a burning sensation in the chest.

Peptic ulcers: These painful sores in the stomach or small intestine lining may result from bacterial infection or medication side effects.

Stomach cancer: While less common, persistent pain, unexplained weight loss, and changes in bowel habits could signal this serious condition.

Colon cancer: An early warning sign of colon cancer may be stomach pain.Â

Simple yet effective lifestyle changes may be needed for your digestive health. For example, eating smaller, more frequent meals, avoiding trigger foods that cause discomfort, and managing stress levels may all contribute to a healthier stomach.Â

Various medications may also be prescribed to address specific stomach issues. These might include medications to reduce stomach acid, treat any underlying infections, or heal ulcers, offering relief and promoting healing.Â

In some cases, more in-depth diagnostic procedures, such as an endoscopy, might be required. This allows healthcare providers to look closer at the stomach and identify any underlying issues that might not be apparent through less invasive methods.

Choosing a Proactive Approach

What does the stomach do? Your stomach plays an essential and unparalleled role in digestion and overall health. Getting professional medical attention is vital when experiencing discomfort or symptoms related to stomach ailments. A healthcare provider can identify the underlying cause and provide an appropriate treatment plan, ensuring optimal health and well-being.

While diagnostic imaging is essential for addressing specific symptoms, preventive screening is crucial for proactive healthcare. Ezra Full Body MRI provides a non-invasive screening option to identify potential health issues before symptoms arise. While an endoscopy is the test to look at your stomach, the Ezra Full Body Scan can screen up to 13 other organs with potential cancers. It could be the key to early detection.