The digestive system includes the gastrointestinal tract, a series of hollow organs joined in a long twisting tube from the mouth to the anus and other organs that help the body break down and absorb food.
Corps, which consist of the digestive tract are the mouth, esophagus, stomach, small intestine, large intestine, also called the colon, rectum and anus. The interior of these hollow organs is a lining called the mucosa. In the mouth, stomach and intestinal mucosa contains tiny glands that produce small juice to help digestion of food. gastrointestinal tract also contains a layer of smooth muscle that helps break down food and move it along the roads.
The two "solid" digestive organs, liver and pancreas, produce digestive juices that reach the intestine through small tubes called ducts. Stores in the liver, gallbladder, digestive juices, until they are needed in the intestine. Some parts of the nervous system and cardiovascular system play a key role in the intestinal tract.
Therefore, it is important to digestion?
When you eat foods such as bread, meat and vegetables, they are not in the form of the body can be used as food. Food and beverages must be changed into smaller molecules of nutrients before they can be absorbed into the blood and leads to cells in the body. Digestion is the process by which food and beverages are divided into parts, so that the smallest unit that can be used to build and nourish cells and provide energy.
How food is digested?
Digestion involves mixing food with digestive juices, moving it in the gut, and the distribution of large molecules of food into smaller particles. Digestion begins in the mouth, chewing and swallowing, and ends in the small intestine.
Movement of Food Through The System
Tall, hollow organs of the digestive system contain muscle layer, which enables their walls to move. wall motion of the body can propel food and liquid in the system and can also mix the contents in each organ. moves from one organ to another food by muscle action called peristalsis. Peristalsis looks like ocean waves traveling through the muscles. muscle contracts to create a narrowing of the body, and then moves slowly down the length of the body. These waves narrowing push the food and liquids before emptying any organization.
The muscle movement occurs when the first major food or liquid if swallowed. Although they are able to start swallowing by choice, when it begins to swallow, it becomes involuntary and proceeds under the control of nerves.
Food intake is pushed into the esophagus, which connects the throat to the stomach below. At the junction of the esophagus and the stomach is a muscle ring called the lower sphincter of the esophagus, closing the passage between the two bodies. As the food approaches the closed sphincter, the sphincter relaxes and allows the passage of food through the stomach.
The stomach has three mechanical tasks. Firstly, grocery stores, and swallow the liquid. To do this, the muscles of the upper stomach relaxes to large volumes of material ingested. The second task is to combine foods, liquids and digestive juices produced by the stomach. The lower part of the stomach mixture of these materials by its muscle action. The third task is to empty the stomach of its contents slowly into the small intestine.
Several factors affect emptying of the stomach, including the food type and degree of muscle action of gastric emptying and small intestine. Carbohydrates, for example, spend little time in the stomach, while the protein remains in the stomach longer, and fats the longest. As the food dissolves in the juice of the pancreas, liver and intestines, intestinal contents are mixed and pushed to allow digestion.
Finally, the digested nutrients are absorbed through the intestinal wall and transported throughout the body. This process is a waste of undigested food, known as fiber, and older cells that lose the mucosa. These materials are pushed into the large intestine, where they remain for the feces are eliminated through the stool.
The Production of Digestive Juices
digestive glands that act first are in the oral cavity, salivary glands. Saliva produced by these glands contains an enzyme that begins the digestion of starch in food into small particles. The enzyme is a substance that speeds up chemical reactions in the body.
The next set of digestive glands of the gastric mucosa. They produce stomach acid and the enzyme that digests protein. A thick layer of mucus in the mucosa and helps keep the digestive juices of the stomach acid to dissolve the tissues. In most people, the gastric mucosa is able to resist the juice, although food and other tissues of the body can not.
The empty stomach for food and juice mixture into the small intestine, the juices of two other digestive organs mixed with food. One of these organs, the pancreas produces a juice that contains a wide range of enzymes to break down carbohydrates, fats and proteins in food. Other enzymes that are active in the process come from glands in the intestinal wall.
The second body, the liver, gastrointestinal tract, yet another product of bile juice. The bile is stored between meals in the gallbladder. During the meal, he was ousted from the gallbladder, bile duct and intestine to mix the fat content in foods. The bile acids dissolve the fat content in intestinal fluid, like detergents that dissolve grease from the pan. After the dissolution of the fat is digested by enzymes in the pancreas and intestinal mucosa.
Absorption and Transport of Nutrients
Most molecules of digested food and water and minerals are absorbed by the small intestine. Mucosa of the small intestine contains many folds that are covered with small projections called villi finger. In turn, the villi are covered with microscopic projections called microvilli. These structures create a huge surface area through which nutrients can be absorbed. Specialized cells allow absorbed materials cross the mucosa into the bloodstream, where it is discharged into the blood to other parts of the body for storage or processing chemicals. This part of the process depends on various nutrients.
Carbohydrates. Dietary Guidelines for Americans 2005 recommends that 45-65 percent of total daily calories from carbohydrates. Foods rich in carbohydrates are bread, potatoes, peas and beans, rice, pasta, fruit and vegetables. Many of these foods contain both starch and fiber.
Carbohydrates, sugars, starch, and are divided into simpler molecules by enzymes in saliva, in juice produced by the pancreas and small bowel mucosa. The starch is digested in two steps. First, the enzyme in saliva and pancreatic juice breaks the starch molecules called maltose. Then an enzyme in the lining of the small intestine is divided into maltose into glucose, which can be absorbed into the blood. Glucose is carried blood to the liver where they are stored or used to provide energy for the work of the Authority.
The sugars are digested in a single step. Enzyme in the intestinal mucosa of small liquid sucrose, also known as table sugar, glucose and fructose which are absorbed by the intestine into the blood. Milk contains a different type of sugar, lactose, which is transformed into absorbable molecules by another enzyme in the intestinal mucosa.
Indigestible fiber and passes through the digestive system is not broken by enzymes. Many foods contain both soluble and insoluble fiber. Soluble fiber dissolves easily in water and is soft, the texture in the intestines, such as freezing. Insoluble fiber, on the other hand, passes essentially unchanged through the intestines.
Proteins. Foods such as meat, eggs, beans, and consists of giant molecules of protein to be digested by enzymes before they can be used to build and repair tissues. Enzyme in the juice of the stomach starts the digestion of protein intake. Then, in the small intestine, several enzymes of pancreatic juice and intestinal mucosa complete breakdown of large protein molecules into smaller molecules called amino acids. These small molecules can be absorbed from the intestine into the bloodstream and be carried to all parts of the body to build walls and other parts of the cell.
Fats. Fat molecules are a rich source of energy for the body. The first step in the digestion of fats like butter and melt into the liquid contents of the intestine. The bile acids produced by the liver break down fats into tiny droplets and allow pancreatic and intestinal enzymes to break down large fat molecules into smaller ones. Some of these small molecules of fatty acids and cholesterol. Bile acids in combination with fatty acids and cholesterol and helps to move these particles in mucous cells. In these cells, small molecules are formed back into large, most of which goes to the lymphatic vessels in the area called the intestine. These small vessels carry the reformed fat to the veins in the chest and the blood carries the fat for storage in different parts of the body.
Vitamins. Another important part of food that is absorbed by the small intestine are vitamins. Two types of vitamins are classified by the fluid, which can be dissolved: water-soluble vitamins (all B vitamins and vitamin C) and fat-soluble vitamins (vitamins A, D, E and K). Fat-soluble vitamins are stored in the liver and adipose tissue of the body, while water-soluble vitamins are easily stored and the amounts above are flushed into the urine.
The water and salt. Most of the material absorbed by the small intestine is water in which salt is dissolved. Salt and water from food and liquids to swallow and juices secreted by the digestive glands of many.
How does the digestive process controlled?
major hormones that control the functions of the digestive system are produced and released by cells lining the stomach and small intestine. These hormones are released into the bloodstream from the gastrointestinal tract, heart and travel through the arteries and back to the digestive system where they stimulate digestive juices and cause organ movement.
major hormones that control digestion of gastrin, secretin and cholecystokinin (CCK):
- Gastrin causes the stomach to produce acid for dissolving and digesting some foods. Gastrin is also necessary for the proper development of cells lining the stomach, small intestine and colon.
- Secretin causes the pancreas to send the digestive juices is rich in bicarbonate. Bicarbonate helps neutralize the acid content of the stomach because he fell in the small intestine. Secretin also stimulates the stomach to produce pepsin, an enzyme that digests proteins and stimulates the liver to produce bile.
- CCK causes the pancreas to produce pancreatic enzymes and causes the gallbladder to empty. It also promotes the growth of normal cells of the pancreas.
Other gastrointestinal hormones regulate appetite:
- Ghrelin is produced in the stomach and upper intestine in the absence of the power of the digestive system and stimulates appetite.
- Peptide YY is produced in the gastrointestinal tract in response to a meal in the system and inhibits appetite.
These two hormones act on the brain to regulate food intake of energy. Researchers examine other hormones that may play a role in appetite suppression, including glucagon-like peptide-1 (GPL-1), oxyntomodulin (+), and pancreatic polypeptide.
Two types of nerves help to control the action of the digestive system.
External or outside, the nerves of the digestive system of the brain or spinal cord. They release two chemicals, acetylcholine and adrenaline. Acetylcholine causes the muscle layer of the digestive system to tighten with more force and increase the "push" of food and juice in the digestive tract. It also causes the stomach and the pancreas to produce more digestive juice. Adrenaline has the opposite effect. blood flow relaxes the muscles of the stomach and intestines and reduces to these organs, slowing or stopping digestion.
Outside or inside, the nerves form a dense network embedded in the wall of the esophagus, stomach, small intestine and colon. Inner nerves called for action on the walls of hollow organs are stretched by food. Release of many substances that accelerate or retard the movement of foodstuffs and the production of juices by the digestive organs.
Together, the nerves, hormones, blood and organs of the digestive system perform the complex tasks of digestion and absorption of nutrients in foods and liquids you consume each day.