- Digestive system and its function
- How does digestion work - animation
- Why is digestion important?
- How does food move through the GI tract?
- How do digestive juices in each organ of the GI tract break down food?
- What happens to the digested food molecules?
- How is the digestive process controlled?
How do digestive juices in each organ of the GI tract break down food?
Digestive juices contain enzymes—substances that speed up chemical reactions in the body—that break food down into different nutrients.
SALIVARY GLANDS
Saliva produced by the salivary glands moistens food so it moves more easily through the esophagus into the stomach. Saliva also contains an enzyme that begins to break down the starches from food.
GLANDS IN THE STOMACH LINING
The glands in the stomach lining produce stomach acid and an enzyme that digests protein.
PANCREAS
The pancreas produces a juice containing several enzymes that break down carbohydrates, fats, and proteins in food. The pancreas delivers digestive juice to the small intestine through small tubes called ducts.
LIVER
The liver produces a digestive juice called bile. The gallbladder stores bile between meals. When a person eats, the gallbladder squeezes bile through the bile ducts, which connect the gallbladder and liver to the small intestine. The bile mixes with the fat in food. The bile acids dissolve fat into the watery contents of the intestine, much like how detergents dissolve grease from a frying pan, so the intestinal and pancreatic enzymes can digest the fat molecules.
SMALL INTESTINE
Digestive juice produced by the small intestine combines with pancreatic juice and bile to complete digestion. The body completes the breakdown of proteins, and the final breakdown of starches produces glucose molecules that absorb into the blood. Bacteria in the small intestine produce some of the enzymes needed to digest carbohydrates.
References
The Digestive Process: What Is the Role of Your Pancreas in Digestion?
Your pancreas plays a big role in digestion. It is located inside your belly (abdomen), just behind your stomach. It's about the size of your hand. During digestion, your pancreas makes pancreatic juices called enzymes. These enzymes break down sugars, fats, proteins, and starches. Your pancreas also helps your digestive system by making hormones. These are chemical messengers that travel through your blood. Pancreatic hormones help regulate your blood sugar levels and appetite, stimulate stomach acids, and tell your stomach when to empty.
Pancreatic enzymes
Your pancreas creates natural juices called pancreatic enzymes to break down foods. These juices travel through your pancreas by tubes called ducts. They empty into the upper part of your small intestine called the duodenum. Each day, your pancreas makes about 8 ounces of digestive juice filled with enzymes. These are the different enzymes:
Lipase. This enzyme works together with bile, which your liver produces, to break down fat in your diet. If you don't have enough lipase, your body will have trouble absorbing fat and the important fat-soluble vitamins (A, D, E, K). Symptoms of poor fat absorption include diarrhea and fatty bowel movements.
Protease. This enzyme breaks down proteins in your diet. It also helps protect you from germs that may live in your intestines, such as certain bacteria and yeast. Undigested proteins can cause allergic reactions in some people.
Amylase. This enzyme helps break down starches into sugar, which your body can use for energy. If you don’t have enough amylase, you may get diarrhea from undigested carbohydrates.
Pancreatic hormones
Many groups of cells make hormones inside your pancreas. Unlike enzymes that are released into your digestive system, hormones are released into your blood. They carry messages to other parts of your digestive system. Pancreatic hormones include:
Insulin. This hormone is made in cells of the pancreas known as beta cells. Beta cells make up about 75% of pancreatic hormone cells. Insulin is the hormone that helps your body use sugar for energy. Without enough insulin, your sugar levels rise in your blood and you develop diabetes.
Glucagon. Alpha cells make up about 20% of the cells in your pancreas that make hormones. They make glucagon. If your blood sugar gets too low, glucagon helps raise it by sending a message to your liver to release stored sugar.
Gastrin and amylin. Gastrin is mainly made in the G cells in your stomach, but some is made in the pancreas It stimulates your stomach to make gastric acid. Amylin is made in beta cells and helps control appetite and stomach emptying.
Common pancreatic problems and digestion
Diabetes, pancreatitis, and pancreatic cancer are 3 common problems that affect the pancreas. Here is how they can affect digestion:
Diabetes. If your pancreatic beta cells don't make enough insulin or your body can’t use the insulin your pancreas makes, you can develop diabetes. Diabetes can cause gastroparesis. This means the digestive system works more slowly than it should. Diabetes also affects what happens after digestion. If you don't have enough insulin and you eat a meal high in carbohydrates, your sugar can go up and cause symptoms such as hunger and weight loss. Over the long term, it can lead to heart and kidney disease, among other problems.
Pancreatitis. Pancreatitis happens when the pancreas becomes inflamed. It is often very painful. In pancreatitis, the digestive enzymes your pancreas make attack your pancreas and cause severe abdominal pain. The main cause of acute pancreatitis is gallstones blocking the common bile duct. Too much alcohol can cause acute pancreatitis and pancreatitis that does not clear up. This is known as chronic pancreatitis. Pancreatitis affects digestion because enzymes are not available. This leads to diarrhea, weight loss, and malnutrition. About 90% of the pancreas must stop working to cause these symptoms.
Pancreatic cancer. About 19 out of 20 pancreatic cancers begin in the cells that make enzymes for digestion. Not having enough pancreatic enzymes for normal digestion is very common in pancreatic cancer. Symptoms can include weight loss, loss of appetite, indigestion, and fatty stools.
Your pancreas is important for digesting food and managing your use of sugar for energy after digestion. If you have any symptoms of pancreatic digestion problems, such as loss of appetite, abdominal pain, fatty stools, or weight loss, call your healthcare provider. If you have a family history of pancreatitis or pancreatic cancer, let your provider know.