Science

• Accessory organs of digestion are organs that secrete substances needed for the chemical digestion of food but through which food does not actually pass as it is digested. Besides the liver, the major accessory organs of digestion are the gallbladder and pancreas. These organs secrete or store substances that are needed for digestion in the first part of the small intestine, the duodenum, where most chemical digestion takes place. This organ includes the salivary glands, the liver, pancreas, and gallbladder. 
• Salivary Glands

  located around the oral cavity, secrete saliva. This substance moves out of the glands into the oral cavity through ducts. Saliva is 99% water, but also contains enzymes and proteins that lubricate the oral cavity and begin chemical digestion of food.
• The liver is the largest gland in the body, weighing about three pounds in an adult. It is also one of the most important organs. In addition to being an accessory digestive organ, it plays a number of roles in metabolism and regulation. It lies inferior to the diaphragm in the right upper quadrant of the abdominal cavity and receives protection from the surrounding ribs.
• Gallbladder


  A small, hollow, pouch-like organ that lies just under the right side of the liver
• Gallbladder


  • About 8 cm (3.1 in.) long
  • Shaped like a tapered sac
  • Open end continuous with the cystic duct
• Bile


  Stored and concentrated in the gallbladder until needed in the duodenum to help digest lipids
• Bile movement


  1. Leaves the liver through the cystic duct

  2. Reaches the gallbladder

  3. Stored in the gallbladder

  4. Forced back through the cystic duct and into the common bile duct

  5. Drains into the duodenum
• Gallbladder capacity


  May store between 30 and 60 mL (1-2 oz) of bile
• Presence of fat in the duodenum


  Signals the gallbladder to contract and force its contents into the duodenum
• Pancreas

  The soft, oblong, glandular pancreas lies transversely in the abdomen behind the stomach. Its head is nestled into the “c-shaped” curvature of the duodenum with the body extending to the left about 15.2 cm (6 in) and ending as a tapering tail in the hilum of the spleen.

  A healthy pancreas produces the correct chemicals in the proper quantities, at the right times, to digest the foods we eat. The pancreas has both endocrine and exocrine functions. 
• Exocrine function


  The pancreas contains exocrine glands that produce enzymes important to digestion
• Enzymes produced by the pancreas

  • Trypsin
  • Chymotrypsin
  • Amylase
  • Lipase
• Trypsin and chymotrypsin


  Digest proteins
• Amylase


  Digests carbohydrates
• Lipase


  Breaks down fats
• Release of pancreatic juices


  1. Food enters stomach

  2. Pancreatic juices released into ducts

  3. Main pancreatic duct joins common bile duct to form ampulla of Vater

  4. Ampulla of Vater located in duodenum
• Common bile duct


  Originates in liver and gallbladder, produces bile
• Pancreatic juices and bile released into the duodenum help the body digest fats, carbohydrates, and proteins
• Endocrine Function:

  The endocrine component of the pancreas consists of islet cells (islets of Langerhans) that create and release important hormones directly into the bloodstream. Two of the main pancreatic hormones are insulin, which acts to lower blood sugar, and glucagon, which acts to raise blood sugar. Maintaining proper blood sugar levels is crucial to the functioning of key organs including the brain, liver, and kidneys.
• Three pairs of major salivary glands (parotid, submandibular, and sublingual glands) and numerous smaller ones secrete saliva into the oral cavity, where it is mixed with food during mastication.
• Functions 

  1. It has a cleansing action on the teeth.
  2. It moistens and lubricates food during mastication and swallowing.
  3. It dissolves certain molecules so that food can be tasted.
  4. It begins the chemical digestion of starches through the action of amylase, which breaks down polysaccharides into disaccharides.
• Saliva contains water, mucus, and enzyme amylase. 
•  bile his yellowish-brown fluid aids chemical digestion by emulsifying fats in the duodenum.