Digestive System

• Teeth are used to break up large pieces of food into smaller ones.
• Alimentary canal/digestive tract

  Main part of the digestive system, includes the mouth, esophagus, stomach, small intestine, large intestine, and anus
• The alimentary canal is about 30 ft long from mouth to anus
• The length of an esophagus is 30 cm
• Swallowing


  Food passes from the pharynx down to the esophagus
• Esophagus

  A tube leading to the stomach, coated with slippery mucus to help the bolus pass easily
• Digestive System Processes

  • Ingestion
  • Digestion
  • Absorption
  • Assimilation
  • Egestion/Excretion
• Ingestion


  The first stage of feeding, involving food being taken up into the mouth
• Digestion


  The chemical breakdown of large insoluble food molecules into smaller soluble molecules that can be absorbed
• Absorption


  The small products of digestion are then absorbed into the blood vessels
• Assimilation


  The stage of processing food that is sometimes left out
• Egestion


  The final stage, involving undigested food, mostly cellulose in humans, being passed out of the anus on faeces at the end of the alimentary canal
• Bolus


  Chewed food
• Types of Digestion

  • Physical/Mechanical Digestion
  • Chemical Digestion
• Body Systems

  • Circulatory System (Heart, Blood Vessels)
  • Nervous System (Brain)
  • Digestive System (Mouth, Teeth, Tongue, Esophagus, Stomach, Small intestine, Large intestine, Rectum, Anus, Pancreas)
  • Reproductive System (Male organ, Female organ)
  • Excretory System (Liver)
  • Respiratory System (Nose, Lungs)
• When we swallow, the bolus passes through the esophagus and enters the stomach.