Structure of the human digestive system

• What enzyme do salivary glands secrete?

  Amylase
• What is the function of the oesophagus?

  Carries food from the mouth to the stomach
• What process moves food along the oesophagus?

  Peristalsis
• What enzymes are secreted in the stomach?

  Protease enzymes
• What acid is produced in the stomach?

  Hydrochloric acid
• Where does digestion and absorption of nutrients mainly occur?

  Small intestine
• What is the role of the large intestine in digestion?

  Absorbs water and forms faeces
• What organ makes bile?

  Liver
• What organ stores bile?

  Gall bladder
• What are two main functions of bile in digestion?

  Neutralises stomach acid and emulsifies fats
• What organ secretes digestive enzymes into the small intestine?

  Pancreas
• What type of molecules do enzymes break down during digestion?

  Large insoluble molecules into smaller soluble ones
• Where are nutrients absorbed into the bloodstream?

  Small intestine
• What structures in the small intestine increase surface area for absorption?

  Villi
• How do villi help to shorten the diffusion pathway?

  They are one cell thick
• How do capillaries in villi aid absorption?

  Transport absorbed nutrients away to maintain the concentration gradient
• Why is it beneficial for villi to contain muscles?

  To mix the ileum contents and maintain concentration gradient
• What is the function of microvilli on epithelial cells in the small intestine?

  Increase surface area for diffusion
• Why do epithelial cells in the small intestine have many mitochondria?

  Provide energy for active and co transport
• What is the role of carrier proteins in epithelial cells?

  Transport molecules through active transport
• What is the role of channel proteins in epithelial cells?

  Allow facilitated diffusion
• What is the role of membrane-bound enzymes in epithelial cells?

  Assist in breaking down molecules on cell membrane