Digestive system

• Digestion


  The process of breaking down food into smaller molecules that can be absorbed by the body
• Digestive system


  • Breaks down food into smaller soluble molecules to be absorbed by the body cells to release energy through cellular respiration
• Main parts of the human digestive system

  • Mouth
  • Gullet
  • Stomach
  • Small intestine
  • Large intestine
  • Rectum
  • Anus
  • Liver

  
• Physical digestion


  Breaking down of food by physical/mechanical means (cutting, grinding, crushing, mixing)
• Chemical digestion


  Breaking down of food into smaller molecules through the action of enzymes
• Enzyme


  A biological catalyst that speeds up the rate of chemical reactions without themselves being consumed or permanently altered by the reaction
• Types of enzymes


  • Carbohydrases (amylase, maltase)
  • Proteases
  • Lipases
• Carbohydrases


  Enzymes that break down carbohydrates into simple sugars (starch > maltose and maltose > glucose)
• Proteases


  Enzymes that break down proteins into amino acids
• Lipases


  Enzymes that break down fats into fatty acids and glycerol
• Starch


  Broken down by amylase into maltose
• Maltose


  Broken down by maltase into glucose
• Proteins


  Broken down by proteases into amino acids
• Fats


  Broken down by lipases into fatty acids and glycerol
• The mouth has physical and chemical digestion through salivary amylase, and the saliva softens and lubricates food to be easily swallowed
• The gullet/oesophagus continues the chemical digestion from salivary amylase in the mouth
• The stomach aids in physical (churning) digestion, chemical digestion (gastric juice contains proteases and kills bacteria), and has a mucus layer that protects tissues from acid

  
• The small intestine does not have physical digestion, only chemical digestion (numerous enzymes are released) for carbohydrates, proteins and fats

  
• The large intestine absorbs water and mineral salts
• The rectum temporarily stores food and waste to form faeces
• The anus releases faeces through this opening
• The end products of digestion are soluble molecules of digested food that are small enough to be absorbed into the bloodstream
• Cells use simple sugars during respiration to release energy and carry out cell functions, enabling the body to grow

  
• Amino acids are used for protein repair and cell growth
• Fatty acids and glycerol are used to make fats in the body
• Excessive simple sugars in the body

  Can lead to very high levels of sugar in the bloodstream
• Diabetes


  A condition where the body is unable to produce sufficient insulin, a hormone to balance the blood sugar level
• Symptoms of diabetes include slow healing of wounds, constant hunger, frequent urination, tingling/numbness in hands and feet, unexplained weight loss and blurred vision
• To reduce the risk of diabetes, one needs to maintain a healthy and active lifestyle by having regular health screenings, having a balanced diet, exercising regularly and avoiding smoking and drinking alcohol
• Components of a healthy and balanced diet

  • Carbohydrates
  • Proteins
  • Fats
  • Vitamins
  • Water
  • Fibre
  • Mineral salts
• Constipation


  When too much water is absorbed by the body, making faeces hard and dry
• Constipation can be caused by stress, consumption of some medication, not drinking enough water and not having enough fibre in the diet
• Gastritis


  Swelling of the stomach lining, causing abdominal pains, nausea and bloating
• Gastritis may be caused by bacterial or viral infection, skipping meals, consuming alcohol, caffeine and oily food
• Food poisoning


  Vomiting and diarrhoea as a result of consuming food contaminated by bacteria
• Food safety tips


  • Use separate utensils for raw and cooked food
  • Cover food properly and place in refrigerator
  • Ensure bottles/drinks are tightly sealed
  • Do not consume food from cans that are badly dented
  • Do not buy chilled or frozen food not stored at appropriate temperature
  • Do not consume food that is mouldy
  • Select food not past expiration date
• Bacteria can have beneficial effects, such as helping to digest some carbohydrates, absorb nutrients and minerals, produce enzymes and vitamins, and are found in foods like coffee, chocolate, yoghurt, cheese, vinegar, pickles, miso, sourdough and belacan
• stomach is a muscular bag that aids in physical (churning) digestion, chemical digestion (gastric juice contains proteases and kills bacteria), and mucus layer (protects tissues from acid)?