#biology #digestivesystem

Digestive System : organs

• The digestive system is an example of an organ system.

• Some of the digestive system organs make up the alimentary canal; food passes directly through these organs as it moves through the body:

  mouth

  
  

  oesphagus

  
  

  stomach

  
  

  small intestine, including the duodenum and the ileum

  
  

  large intestine, including the colon, rectum and anus

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• Some of the organs of the digestive system do not form part of the route travelled by food, but are still involved with digestion; these are the associated organs, or accessory organs, and include the:

  salivary glands

  
  

  pancreas

  
  

  liver

  
  

  gall bladder

Digestive system organs diagram

The organs of the human digestive system work together to digest food and absorb nutrients

Digestive system:function

• The function of the digestive system is to digest food and absorb nutrients.

• The digestive system carries out its function in several stages:

  ○ingestion: food and drink are taken into the body through the mouth

  
  

  ○ mechanical digestion: food is broken down into smaller pieces without chemical change to the food molecules.

  
  

  ○ chemical digestion: large, insoluble molecules are broken down into small, soluble molecules.

  
  

  ○ absorption: small food molecules and ions move through the wall of the intestine into the blood.

  
  

  ○ egestion: food that has not been digested or absorbed passes out of the body as faeces.

  
  

• Once nutrients have been absorbed into the blood by the digestive system they can be assimilated into the body; this occurs when they are taken up by the cells of the body.

Digestive system functions table