Digestive system

• What are the two roles of the small intestine ?

  • It is where most digestion takes place
  • It is where nutrients are absorbed into the bloodstream
• What is the oesophagus ?

  A muscular tube that connects the mouth to the stomach.
• Which enzyme does the pancreas produce ?

  • Carbohydrates e.g amylase
  • Proteases
  • Lipases
• Give four ways in which villi are adapted to their role ?

  • Many villi - giving them a large total surface area over to which absorb nutrients
  • Walls have only a single layer of cells - nutrients only have to diffuse a short distance
  • Good supply of blood - maintains a strong concentration gradient between the lumen and the blood.
  • Cells lining the villi have microvilli on their surface - further increasing the surface area
• What are the three things does the stomach does to aid digestion ?

  • The stomach contracts its muscular walls to churn and mix the food
  • Produces pepsin and breaks proteins down into amino acids
  • Produces hydrochloric acid which provides the right pH for pepsin to function and kills microorganisms.
• Which enzymes does the stomach produce ?

  Protease
• What is the main role of the large intestine ?

  To reabsorb water
• Which enzyme does the small intestine produce ?

  • Carbohydrases
  • Proteases
  • Lipases
• What are the two main roles of the digestive system ?

  • Digestion - process of breaking down large food molecules into smaller molecules
  • Absorption - process of absorbing these small food molecules into the body.
• What is the role of the salivary glands ?

  Produces saliva for two purposes;

  • Moistens food which makes it easier to swallow
  • Contains salivary amylase which digests starch to maltose