digestive system

• what are the functions of the digestive system?

  • to digest and absorb nutrients.
  • breaks down small molecules which get absorbed by the body.
• what is the structure of the digestive system?

  • 11 metres long.
  • a continuous tube like structure.
  • is made up of a gastrointestinal tract which contains the: Gall bladder, Pancreas and Liver.
• examples hollow organs

  • Mouth.
  • Anus.
  • Oesophagus.
  • Large and Small Intestines.
• examples of solid organs

  • Gall bladder.
  • Liver.
  • Pancreas.
• why is the digestive system important?


  it is important because:

  • it breaks down nutrients to allow the body to absorb them for growth and energy.
  • water and food is important for the body to allow the body to work properly and stay healthy.
  • Proteins, Fats, Carbohydrates, Vitamins and Minerals are nutrients.
  • Proteins break down into amino acids.
  • Fats break down into fatty acids and glycerol.
  • Carbohydrates breaks down into simple sugars.
• what does the mouth do?


  it:

  • transports food to the oesophagus.
  • moves food to the GI tract.
  • the tongue pushes food to the throat.
  • includes the epiglottis.
  • make siliva glands.
• what does the epiglottis do?


  reduce choking by folding over the trachea.
• what does the oesophagus do?


  the oesophagus:

  • once swallowing starts its an automatic response.
  • the brain signals muscles such as peristalsis.
• what does the lower oesophagus do?


  it:

  • when food reaches the lower oesophageal sphincter it relaxes and allows food to pass through into the stomach.
  • the lower oesphageal sphincter closes up to allow the stomach contents to not pass through into the oesophagus.
• where is the lower oesophageal sphincter located?


  at the end of the oesophagus.
• what is the lower oesophageal sphincter is also known as?


  a ring like muscle.
• what does the stomach do?


  it:

  • mixes food and fluid with digestive juices.
  • slowly empties its contents/ chymes into the small intestine.
• what does the small intestine do?

  • the muscles mix food with digestive juices from the Liver, Pancreas and the intestines.
  • this pushes food forward for digestion.
  • absorbs water and nutrients into the bloodstream.
  • while peristalsis continues the food moves into the large intestine.
• what does the large intestine do?

  • contains waste products from the digestive process such as undigested fluid and food as well as older cells from the GI tract.
  • absorbs water.
  • changes waste from liquid to stool.
  • peritalsis aids the movement of stool into the rectum.
• what does the rectum do?


  stores stool until it is released by a bowel movement.
• where is the rectum located?


  at the lower end of the large intestine.
• what does saliva do?


  moves food more easily down your oesophagus into your stomach.
• what does saliva break down?


  starch.
• what breaks down starch?


  saliva
• what does the pancreas do?

  • makes digestive juices to break down fats, carbohydrates and protein.
  • delivers the digestive juices through the small intestine through small ducts.
  • make hormones that are important to digestion.
• what does the gall bladder store? 


  bile
• where is bile stored?


  in the gall bladder.
• what does the gall bladder do?

  • squeezes bile through the bile ducts in the small intestine.
• what controls the digestive system?


  hormones
• how does hormones control the digestive system?

  • lines the stomach and small intestine.
  • tells the body when to make digestive juices.
  • send signals to the brain resulting in the feeling of hunger or thirst.
• what is cholecylostokinin?


  signals secretion of pancreatic enzymes.
• what secretes signals of the release of pancreatic enzymes?


  cholecylostokinin.
• what are gastrin signals?


  these signal the secretion of gastric acid.
• what signals the secretion of gastric acid?


  gastrin signals.
• what is secretin?


  this signals the secretion of water and bicarbonate from the pancreas.
• what is Gherlin?


  this signals when an individual is hungry.
• what causes the signal of hunger?


  Ghrelin
• what is glucose?


  this is dependent on insullihoptropic polypeptide which stops or decreases gastric secretion.
• what does glucose do?


  stops or decreases the secretion of gastric acid but releases insulin in response to high glucose levels.
• what connects the CNS to the digestive system?


  nerves.
• what do nerves also control?


  some digestive functions.
• where is the enteric nervous system found?


  in the GI tract walls.
• what does the enteric nervous system do?


  when food stretches the GI tract the nerves quickly release different substances to speed up or slow down the movement of food and the production of digestive juices.
• what does the signals released by the enteric nervous system do?


  control the actions of the gut muscles making them contract and relax to allow food to push through your intestines.
• what is IBS?


  this is a chronic condition where muscular contractions of the colon are abnormal.