Human Nutrition

• Carbohydrates


  Needed for energy - glucose is needed for respiration to release energy in the form of ATP
• Consistently too much carbohydrate in diet

  May lead to obesity
• Proteins


  Needed for growth and repair, enzymes, antibodies, some hormones, muscles
• Consistently too little protein in diet

  May lead to stunted growth
• Lipids


  Needed for long-term energy store, cell membranes, insulation, myelin sheath on neurones
• Consistently too much lipid in diet

  May lead to obesity
• Vitamin A


  Needed to make the pigment in rod cells in eye, needed for vision at night
• Consistently too little vitamin A in diet

  May lead to night blindness
• Vitamin C


  Needed to make collagen for healthy skin and wound healing
• Consistently too little vitamin C in diet


  May lead to scurvy (bleeding gums, teeth falling out)
• Vitamin D


  Needed for absorption of calcium
• Consistently too little vitamin D in diet


  May lead to rickets/osteoporosis
• Calcium

  Needed for bone strength and making enamel to strengthen teeth
• Consistently too little calcium in diet

  May lead to rickets/osteoporosis
• Iron


  Needed for making haemoglobin in red blood cells
• Consistently too little iron in diet


  May lead to anaemia
• Food moves through the alimentary canal by mechanical and chemical digestion
• Peristalsis


  The process of food moving through the alimentary canal
• Digestion in the mouth

  Mechanical and chemical digestion to break down food
• Digestion in the stomach

  Chemical digestion by enzymes to denature proteins
• Bile is produced in the liver and stored in the gallbladder
• Role of bile


  Emulsifies fats into smaller droplets to increase the surface area for digestion by lipase enzymes in the small intestine
• Role of villi


  Provide a large surface area for absorption of nutrients
• Enzymes produced by the pancreas

  • Lipase
  • Protease
  • Amylase
• Protease enzymes


  Break down proteins
• Lipase enzymes


  Break down lipids into glycerol and fatty acids
• Parts of the small intestine

  • Duodenum
  • Ileum
• Parts of the large intestine

  • Colon
  • Rectum
• Role of the colon

  Water absorption
• Role of the rectum


  Storage of faeces
• Removal of faeces from the anus


  Egestion