Human digestive system

• secretes = makes
• This is the human digestive system

  A) mouth

  B) oesophagus

  C) liver

  D) gall bladder

  E) pancreas

  F) stomach

  G) bile duct

  H) small intenstine

  I) large intestine

  J) anus

  
• mouth = mechanical digestion --> amylase begins starch digestion
• Oesphagus = peristalsis causes muscles to contract and force food along
• peristalsis = muscles contract above food, forcing food down (nothing to do with gravity)
• stomach = protease begins protein digestion, hydrochloric acid (pH2) kills bacteria
• Liver = bile is made here.
• Gall bladder = bile is stored here
• bile duct = bile travels through this to get to the pancreas
• Pancreas = releases all 3 enzymes (amylase, protease and lipase) into small intenstine
• Small intestine = contains all 3 enzymes, so all food groups finish being digested here; then products are absorbed into bloodstream through the villi. Alkaline conditions (pH9)

  First time fat gets digested
• Large intestine = water is reabsorbed here
• Anus = undigested food is removed
• These are villi; creates a large surface area for abosorption

  
• small intestine has good blood supply to maintain a concentration gradient for diffusion -> only place where absorption occurs (villi create a large surface area for maximum absorption)
• The small intestine is in alkaline conditions because alkali = optimum for enzymes
• food groups finish being digested in the small intestine because all 3 enzymes are released here (transported from pancreas) -> products are then absorbed into blood stream through the villi
• small intenstine has a pH of 9
• first place fat is digested is the small intestine