What does regulate digestive system mean

Eventually, the contents of the stomach are emptied into the small intestine. The muscles of the small intestine mix food with its own digestive juices, along with those from the pancreas and liver. As the small intestine pushes the food toward the large intestine, these digestive juices help to further break down the food into carbohydrates, fats, and proteins.

The walls of the small intestine then absorb nutrients from the digested food and deliver them into the bloodstream. From there, the blood carries the nutrients to cells throughout the body.

Not all food is broken down by the digestive system. Waste, or undigested food and dead cells, is pushed down to the large intestine. The large intestine absorbs the water and remaining nutrients from the waste before transforming it into solid stool. While the hollow organs play critical roles in the digestive process, the solid organs release various chemicals that allow the digestive process to actually work. The pancreas is located in the upper part of the abdomen, behind the stomach.

It produces digestive juices that help the small intestine break down food into carbohydrates, proteins, and fats. It also makes chemicals that help regulate blood sugar levels, which affect how much energy the body has available to use. The liver is a very large organ located above the stomach in the upper abdomen. During digestion, bile is sent into the small intestine to help break down foods that contain fats.

Besides aiding in the digestive process, the liver also stores nutrients and helps remove toxins from the body. The gallbladder is a small pouch that stores the bile made in the liver. During digestion, the gallbladder releases bile into the top part of the small intestine to break down foods that contain fats. This can cause anything from minor discomfort to serious health issues.

Some common digestive system problems include:. Acid reflux occurs when stomach acid or bile flows back up into the esophagus, causing heartburn and other uncomfortable symptoms. Most people experience acid reflux from time to time, especially after eating spicy food or heavy meals. When acid reflux happens more than twice per week, however, the condition is considered gastroesophageal reflux disease GERD.

While acid reflux can cause some discomfort, GERD has the potential to cause serious health problems. Gallstones are solidified chunks of digestive fluid that can form in the gallbladder.

They can be as tiny as a grain of sand or as big as a golf ball. People may have one gallstone or several gallstones at the same time. Anyone of any age can be struck by appendicitis, but it seems to be more common during childhood and adolescence. Content on this website is provided for information purposes only.

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Summary Read the full fact sheet. On this page. The mouth and oesophagus The stomach The small intestine Pancreas Liver The large intestine Common problems in the digestive system Where to get help Things to remember. The mouth and oesophagus Digestion begins in the mouth.

The stomach The food passes through a sphincter, or small muscle ring, into the stomach. The small intestine Once in the duodenum, the food is mixed with more digestive enzymes from the pancreas and bile from the liver. The lower part of the stomach mixes these materials by its muscle action. The mixture is referred to as chyme.

Several factors affect emptying of the stomach, including the nature of the food mainly its fat and protein content and the degree of muscle action of the emptying stomach and the next organ to receive the contents the small intestine. As the food is digested in the small intestine and dissolved into the juices from the pancreas, liver, and intestine, the contents of the intestine are mixed and pushed forward to allow further digestion. Finally, all of the digested nutrients are absorbed through the intestinal walls.

The waste products of this process include undigested parts of the food, known as fiber, and older cells that have been shed from the mucosa. These materials are propelled into the colon, where they remain, usually for a day or two, until the feces are expelled by a bowel movement.

The small intestine has 3 segments:. Duodenum — The chyme first enters into the duodenum where it is exposed to secretions that aid digestion. The secretions include bile salts, enzymes, and bicarbonate. Pancreatic enzymes help digest carbohydrates and fats. Bicarbonate from the pancreas neutralizes the acid from the stomach. Jejunum — The chyme is then further transited down into the second or middle part of the small intestine, the jejunum.

Ileum — The ileum is the last section of the small intestine and leads to the large intestine or colon. The ileum mainly absorbs water, bile salts, and vitamin B The ileocecal valve is a one-way valve located between the ileum and the cecum, which is the first portion of the colon.

This valve helps control the passage of contents into the colon and increases the contact time of nutrients and electrolytes essential minerals with the small intestine.

It also prevents back-flow reflux from the colon up into the ileum, and helps minimize the movement of bacteria from the large intestine up into the small bowel. The primary function of the large intestine or colon is to absorb fluids and electrolytes, particularly sodium and potassium, and to convert remaining luminal contents into more solid stool. The colon absorbs on average 1—1. Another function of the colon is to break down ferment dietary fiber to produce short chain fatty acids — substances that can be absorbed and provide added nutrition.

The first portion of the colon, the cecum, is shaped like a pouch, and is the area of storage for the contents arriving from the ileum. The second portion is the ascending colon, where fluids are absorbed and where some stool formation begins. The glands that act first are in the mouth — the salivary glands. Saliva produced by these glands contains an enzyme that begins to digest the starch from food into smaller molecules.

The next set of digestive glands is in the stomach lining. They produce stomach acid and an enzyme that digests protein. One of the unsolved puzzles of the digestive system is why the acid juice of the stomach does not dissolve the tissue of the stomach itself.

In most people, the stomach mucosa is able to resist the juice, although food and other tissues of the body cannot. After the stomach empties the food and juice mixture into the small intestine, the juices of two other digestive organs mix with the food to continue the process of digestion.

One of these organs is the pancreas. It produces a juice that contains a wide array of enzymes to break down the carbohydrate, fat, and protein in 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.

Most absorbed materials cross the mucosa into the blood and are carried off in the bloodstream to other parts of the body for storage or further chemical change.

As already noted, this part of the process varies with different types of nutrients. It is recommended that about 55 to 60 percent of total daily calories be from carbohydrates. Why is emulsification important for digestion of lipids?

Pancreatic juices contain enzymes called lipases enzymes that break down lipids. If the lipid in the chyme aggregates into large globules, very little surface area of the lipids is available for the lipases to act on, leaving lipid digestion incomplete. By forming an emulsion, bile salts increase the available surface area of the lipids many fold.

The pancreatic lipases can then act on the lipids more efficiently and digest them, as detailed in Figure 3. Lipases break down the lipids into fatty acids and glycerides. These molecules can pass through the plasma membrane of the cell and enter the epithelial cells of the intestinal lining. The bile salts surround long-chain fatty acids and monoglycerides forming tiny spheres called micelles. The micelles move into the brush border of the small intestine absorptive cells where the long-chain fatty acids and monoglycerides diffuse out of the micelles into the absorptive cells leaving the micelles behind in the chyme.

The long-chain fatty acids and monoglycerides recombine in the absorptive cells to form triglycerides, which aggregate into globules and become coated with proteins. These large spheres are called chylomicrons. Chylomicrons contain triglycerides, cholesterol, and other lipids and have proteins on their surface. Together, they enable the chylomicron to move in an aqueous environment without exposing the lipids to water.

Chylomicrons leave the absorptive cells via exocytosis. Chylomicrons enter the lymphatic vessels, and then enter the blood in the subclavian vein. Vitamins can be either water-soluble or lipid-soluble. Fat soluble vitamins are absorbed in the same manner as lipids. It is important to consume some amount of dietary lipid to aid the absorption of lipid-soluble vitamins. Water-soluble vitamins can be directly absorbed into the bloodstream from the intestine. Figure 4. Mechanical and chemical digestion of food takes place in many steps, beginning in the mouth and ending in the rectum.

The final step in digestion is the elimination of undigested food content and waste products. The undigested food material enters the colon, where most of the water is reabsorbed. The semi-solid waste is moved through the colon by peristaltic movements of the muscle and is stored in the rectum.

As the rectum expands in response to storage of fecal matter, it triggers the neural signals required to set up the urge to eliminate. The solid waste is eliminated through the anus using peristaltic movements of the rectum. Diarrhea and constipation are some of the most common health concerns that affect digestion. Constipation is a condition where the feces are hardened because of excess water removal in the colon.

In contrast, if enough water is not removed from the feces, it results in diarrhea. Many bacteria, including the ones that cause cholera, affect the proteins involved in water reabsorption in the colon and result in excessive diarrhea.

Emesis, or vomiting, is elimination of food by forceful expulsion through the mouth. It is often in response to an irritant that affects the digestive tract, including but not limited to viruses, bacteria, emotions, sights, and food poisoning. This forceful expulsion of the food is due to the strong contractions produced by the stomach muscles. The process of emesis is regulated by the medulla. Digestion begins with ingestion, where the food is taken in the mouth.

Digestion and absorption take place in a series of steps with special enzymes playing important roles in digesting carbohydrates, proteins, and lipids. Elimination describes removal of undigested food contents and waste products from the body. While most absorption occurs in the small intestines, the large intestine is responsible for the final removal of water that remains after the absorptive process of the small intestines.

The cells that line the large intestine absorb some vitamins as well as any leftover salts and water. The large intestine colon is also where feces is formed.