The pancreas is one of the largest glands in the human body. As well as digestive juices, it secretes a hormone called insulin. Insulin helps to regulate the amount of sugar in the blood. Diabetes is a condition caused by problems with insulin production. Once all the nutrients have been absorbed, the waste is moved into the large intestine, or bowel.
Water is removed and the waste faeces is stored in the rectum. It can then be passed out of the body through the anus. This page has been produced in consultation with and approved by:.
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Content on this website is provided for information purposes only. Information about a therapy, service, product or treatment does not in any way endorse or support such therapy, service, product or treatment and is not intended to replace advice from your doctor or other registered health professional. The pancreas is a tadpole-shaped organ, around 25 cm long, situated behind the stomach in the abdomen. The pancreas produces pancreatic juice which contains enzymes to digest protein, starch and fat.
The pancreatic juice is secreted into the duodenum through the duodenal papilla sometimes called the ampulla of Vater.
In the duodenum, the chyme, the pancreatic juice and bile from the liver are mixed. The acidic chyme from the stomach is neutralised by the alkaline environment of the duodenum. Bile is a greenish-yellow fluid that is made in the liver. Its function is to help in the digestion of fats. It does this by emulsifying fats and breaking down larger globules of fat into smaller droplets, which can be more easily digested. Bile is stored and concentrated in the gallbladder , a small pear-shaped sac located on the under-surface of the liver on the right-hand side of your abdomen.
When fatty foods are consumed, the gallbladder is triggered to release bile into the small intestine via the common bile duct. If a person has had their gallbladder removed called a cholecystectomy bile will drain continuously into the small intestine — and it will become more diluted — as there is no gallbladder to concentrate it.
So eating fat after gallbladder removal may need to be managed carefully for a while to avoid discomfort, flatulence wind and diarrhoea. The biliary tract refers to the system of ducts that transport bile from the liver to the gallbladder and small intestine. If a bile duct becomes obstructed blocked , a person will develop jaundice. From the duodenum, the mixture is passed into the next section of the small intestine, called the jejunum, and then on to the ileum.
The inside surface area of the jejunum and the ileum is increased by folds and also by millions of finger-like projections called villi and microvilli see diagram. The villi increase the surface area of the inside of the jejunum and ileum, creating a greater area for absorption of nutrients. Digestion of foods is completed in this section of the small intestine, and the fats and other nutrients, such as glucose and amino acids are absorbed here through the intestinal wall into the bloodstream and then carried to the liver.
The ileum is the site for absorption of vitamin B Any undigested food, such as fibre, is passed through the ileo-caecal valve to the large intestine. The incoming blood from the small intestine brings nutrients to the liver for processing, for example, glucose from the breakdown of food is brought to the liver and stored there as glycogen.
Other nutrients brought to the liver include amino acids and glycerol. Once the nutrients have been absorbed into the body from the small intestine, the remaining waste is passed into the large intestine also known as the colon.
The large intestine is made up of the caecum, ascending colon, transverse colon, descending colon and sigmoid colon and rectum. The appendix is attached to the caecum. Content from the small intestine comes into the large intestine as fluid and gradually becomes solid as water and salts are absorbed out as it travels through the large intestine by muscular waves called peristalsis Mucus is secreted to aid the passage of faeces to the rectum.
It then comes out of the rectum through the anus as faeces. This process is called egestion. Take care not to confuse egestion with excretion. The digestive system contains many bacteria and about half of the dry weight of faeces consists of bacteria.
Bacteria in the digestive system are important. For example, they:. International Foundation for Gastrointestinal Disorders. GI Disorders. Upper GI Disorders. Lower GI Disorders.
Bowel incontinence Chronic constipation Chronic diarrhea Dyssynergic defecation. Other GI Disorders. Abdominal adhesions Acute Hepatic Porphyria Anal fistulas Celiac disease Clostridium difficile Congenital sucrase-isomaltase deficiency. Malabsorption Opioid Induced Constipation Radiation therapy injury Scleroderma Short bowel syndrome Superior mesenteric artery syndrome.
Vovulus Rare diseases. Motility Disorders. Functional GI Disorders. The Digestive System. Reality Report from Miranda A. Why is digestion important When we eat such things as bread, meat, and vegetables, they are not in a form that the body can use as nourishment. How is food digested Digestion involves the mixing of food, its movement through the digestive tract, and the chemical breakdown of the large molecules of food into smaller molecules. The third task of the stomach is to empty its contents slowly into the small intestine.
The small intestine has 3 segments: the duodenum, the jejunum, and the ileum. Each part or section performs an important role in nutrient absorption. Production of Digestive Juices The glands that act first are in the mouth — the salivary glands.
Absorption and Transport of Nutrients Digested molecules of food, as well as water and minerals from the diet, are absorbed from the cavity of the upper small intestine. Carbohydrates It is recommended that about 55 to 60 percent of total daily calories be from carbohydrates.
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.
Fats Fat molecules are a rich source of energy for the body. Vitamins Another vital part of our food that is absorbed from the small intestine is the class of chemicals we call vitamins.
How is the digestive process controlled? Hormone Regulators A fascinating feature of the digestive system is that it contains its own regulators. The hormones that control digestion are gastrin, secretin, and cholecystokinin CCK : Gastrin causes the stomach to produce an acid for dissolving and digesting some foods. It is also necessary for the normal growth of the lining of the stomach, small intestine, and colon.
Secretin causes the pancreas to send out a digestive juice that is rich in bicarbonate. It stimulates the stomach to produce pepsin, an enzyme that digests protein, and it also stimulates the liver to produce bile. CCK causes the pancreas to grow and to produce the enzymes of pancreatic juice, and it causes the gallbladder to empty. Additional hormones in the digestive system regulate appetite: Ghrelin is produced in the stomach and upper intestine in the absence of food in the digestive system and stimulates appetite.
Peptide YY is produced in the GI tract in response to a meal in the system and inhibits appetite. Both of these hormones work on the brain to help regulate the intake of food for energy.
Nerve Regulators Two types of nerves help to control the action of the digestive system — extrinsic and intrinsic nerves. Share this page. Share on facebook. Share on twitter. Share on linkedin. Share on email. Share on print. Topics of this article.
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