How do digestive juices work

One of these organs is the pancreas. It produces a juice that contains a wide array of enzymes to break down the carbohydrates, fat, and protein in our food. Other enzymes that are active in the process come from glands in the wall of the intestine or even a part of that wall. The liver produces yet another digestive juice—bile.

The bile is stored between meals in the gallbladder. At mealtime, it is squeezed out of the gallbladder into the bile ducts to reach the intestine and mix with the fat in our food. The bile acids dissolve the fat into the watery contents of the intestine, much like detergents that dissolve grease from a frying pan. After the fat is dissolved, it is digested by enzymes from the pancreas and the lining of the intestine. Digested molecules of food, as well as water and minerals from the diet, are absorbed from the cavity of the upper small intestine.

The absorbed materials cross the mucosa into the blood, mainly, and are carried off in the bloodstream to other parts of the body for storage or further chemical change. As noted above, this part of the process varies with different types of nutrients. Carbohydrates: An average American adult eats about half a pound of carbohydrate each day. Some of our most common foods contain mostly carbohydrates.

Examples are bread, potatoes, pastries, candy, rice, spaghetti, fruits, and vegetables. Many of these foods contain both starch, which can be digested, and fiber, which the body cannot digest. The digestible carbohydrates are broken into simpler molecules by enzymes in the saliva, in juice produced by the pancreas, and in the lining of the small intestine. Starch is digested in two steps: First, an enzyme in the saliva and pancreatic juice breaks the starch into molecules called maltose; then an enzyme in the lining of the small intestine maltase splits the maltose into glucose molecules that can be absorbed into the blood.

Glucose is carried through the bloodstream to the liver, where it is stored or used to provide energy for the work of the body. Table sugar is another carbohydrate that must be digested to be useful. An enzyme in the lining of the small intestine digests table sugar into glucose and fructose, each of which can be absorbed from the intestinal cavity into the blood. Milk contains yet another type of sugar, lactose, which is changed into absorbable molecules by an enzyme called lactase, also found in the intestinal lining.

Protein: Foods such as meat, eggs, and beans consist of giant molecules of protein that must be digested by enzymes before they can be used to build and repair body tissues.

An enzyme in the juice of the stomach starts the digestion of swallowed protein. Further digestion of the protein is completed in the small intestine. Here, several enzymes from the pancreatic juice and the lining of the intestine carry out the breakdown of huge protein molecules into small molecules called amino acids. These small molecules can be absorbed from the hollow of the small intestine into the blood and then be carried to all parts of the body to build the walls and other parts of cells.

Fats: Fat molecules are a rich source of energy for the body. The first step in digestion of a fat such as butter is to dissolve it into the watery content of the intestinal cavity. Your gallbladder stores bile between meals. When you eat, your gallbladder squeezes bile through the bile ducts into your small intestine. Your small intestine makes digestive juice, which mixes with bile and pancreatic juice to complete the breakdown of proteins, carbohydrates, and fats.

Bacteria in your small intestine make some of the enzymes you need to digest carbohydrates. Your small intestine moves water from your bloodstream into your GI tract to help break down food. Your small intestine also absorbs water with other nutrients. In your large intestine, more water moves from your GI tract into your bloodstream. Bacteria in your large intestine help break down remaining nutrients and make vitamin K.

Waste products of digestion, including parts of food that are still too large, become stool. The small intestine absorbs most of the nutrients in your food, and your circulatory system passes them on to other parts of your body to store or use. Special cells help absorbed nutrients cross the intestinal lining into your bloodstream. Your blood carries simple sugars, amino acids, glycerol, and some vitamins and salts to the liver.

Your liver stores, processes, and delivers nutrients to the rest of your body when needed. The lymph system , a network of vessels that carry white blood cells and a fluid called lymph throughout your body to fight infection, absorbs fatty acids and vitamins.

Your body uses sugars, amino acids, fatty acids, and glycerol to build substances you need for energy, growth, and cell repair. Your hormones and nerves work together to help control the digestive process. Signals flow within your GI tract and back and forth from your GI tract to your brain. Cells lining your stomach and small intestine make and release hormones that control how your digestive system works. These hormones tell your body when to make digestive juices and send signals to your brain that you are hungry or full.

Your pancreas also makes hormones that are important to digestion. You have nerves that connect your central nervous system—your brain and spinal cord—to your digestive system and control some digestive functions. For example, when you see or smell food, your brain sends a signal that causes your salivary glands to "make your mouth water" to prepare you to eat.

When food stretches the walls of your GI tract, the nerves of your ENS release many different substances that speed up or delay the movement of food and the production of digestive juices. The nerves send signals to control the actions of your gut muscles to contract and relax to push food through your intestines. Griffin P. And, hepatocytes store fat-soluble vitamins and excess substances such as glucose sugar for release when the body requires extra energy.

Once food has passed through the small intestine, it is mostly undigestible material and water. It enters the colon large intestine , named for its wide diameter. The large intestine has six parts: the cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum.

The large pouch-shaped cecum marks the beginning of the colon. Attached near the cecum bottom is the vermiform worm-like appendix. The appendix contains lymphoid tissue and intercepts pathogenic microorganisms that enter the digestive tract. Sometimes, fecal matter may become trapped in the appendix, resulting in appendicitis infection and inflammation. The other parts of the colon absorb water and minerals from the undigested food and compact the remaining material into feces.

Defecation is the digestive process final stage: feces undigested waste products are carried to the rectum through peristalsis and eliminated through the anus.

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Navigation links Introduction Ingestion Digestion: stomach Digestion and absorption: small intestine Absorption: large intestine Introduction Nutrition permits us to take in and use food substances that the body converts to energy and body structure. Back to top Ingestion Food processing begins with ingestion eating. 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.

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. Search Login.