The stomach is a stretchy muscular bag, which stores food and helps to break it down (digestion).
The stomach is in the upper left-hand side of the tummy area (abdomen). An adult’s stomach is about 10 inches (25 centimetres) long. It can expand to hold about a litre of food.
The upper part of the stomach joins to the gullet (oesophagus). The lower part of the stomach joins to the first part of the small bowel (the duodenum). The pancreas, gall bladder and liver are close to the stomach. They produce juices and enzymes (chemicals) that help us digest food.
After food is chewed and swallowed, it passes down the gullet into the stomach. The stomach churns up food and mixes it with acid and enzymes that help break it down into much smaller pieces. This is so our bodies can absorb the nutrients we need to give us energy and keep us healthy.
Semi-solid food then passes from the stomach into the small bowel. Enzymes from the stomach and pancreas help the small bowel absorb important substances from food, such as vitamin B12, iron and calcium.
The stomach wall
The wall of the stomach has four layers. The innermost layer is the mucosa (stomach lining). This contains glands that produce enzymes and acid used in digestion. It also protects the stomach lining from the acid. After this is the submucosa layer, followed by a layer of muscle. The outer layer of the stomach is a strong membrane called the serosa.
The lymphatic system
The lymphatic system is part of the immune system – the body’s natural defence against infection and disease. It’s made up of different organs including the spleen and lymph nodes (glands). There are lymph nodes throughout the body and they are connected by a network of tiny lymphatic tubes (ducts).
The lymphatic system has two roles: it helps protect the body from infection and it drains fluid from the tissues.
Stomach cancer can sometimes spread to the lymph nodes close to the stomach. If you have surgery to remove stomach cancer, your surgeon will usually remove some lymph nodes as well.