Chp-7 Human nutrition

• Carbohydrate

  • Starch (bread, rice, potato)
  • Glycogen (stored in liver, muscle)
  • Cellulose
  • Glucose
  • Maltose
• Chemical digestion


  1. Starch

  2. Amylase

  3. Maltose (Glucose-P)

  4. Maltase

  5. Glucose
• Protein


  • Enzyme
  • Amino acid
• Fat


  • Lipid
  • Lipase
  • Fatty acid
  • Glycerol
• Fibre (Roughage) helps prevent constipation
• Balanced diet


  Provides adequate intake of biological molecules and energy to sustain the body and ensure good health and growth
• Types of nutrients humans need

  • Carbohydrates
  • Proteins
  • Vitamins
  • Minerals
  • Fats
  • Mechanical
  • Water
• Molecules do not change during mechanical digestion
• Protein

  • Haemoglobin
  • Keratin
  • Hormone
  • Enzyme in blood
• Vitamin C is used to form an important protein (collagen) used to make skin, tendons, ligaments and blood vessels. It also helps in the healing of wounds and the formation of scar tissue.
• Vitamin C deficiency causes Scurvy: pain in joints, bleeding in gums, and muscles
• Vitamin D helps calcium to be absorbed, for making bones and teeth
• Vitamin D deficiency causes Rickets, Osteoporosis: weak bones and teeth, bones become soft and deformed, common in young children who rarely got out into sunshine
• Carbohydrates


  Source of energy
• Fats and oils


  Source of energy, building materials, energy store, insulation, buoyancy and making hormones
• Proteins


  Energy, building materials, enzymes, haemoglobin, structural material (muscle), hormones, antibodies
• Vitamin C


  Collagen, resistance to diseases
• Vitamin D


  Absorption of calcium
• Calcium

  Development and maintenance of strong bones and teeth
• Iron


  Making haemoglobin
• Fibre (Roughage)


  Provides bulk for faeces, helps peristalsis
• Water


  Chemical reactions, solvent for transport
• Lack of iron leads to a reduction in the number of red blood cells. The main symptoms of anaemia are tiredness, lack of energy, shortness of breath, heart palpitations and a pale complexion.
• Fats & oils

  Needed to make cell membrane, form insulating layer beneath skin, and protective layer around some body organs
• High concentrations of cholesterol in the blood are linked to narrowing of the arteries, an increased risk of developing high blood pressure and heart disease
• Vitamin C can be tested using DCPIP reagent, which changes from blue to colourless with no heat required
• Ingestion


  Food is taken into the alimentary canal
• Digestion

  Large insoluble molecules of food are broken down into small molecules
• Absorption


  Small molecules are absorbed into the blood
• Assimilation

  Nutrients are absorbed by individual cells
• Egestion


  Food that could not be digested is removed from the body
• Alimentary canal

  Part of the digestive system, the tube that food moves through
• Stomach

  Chemical digestion - pepsin breaks down protein into polypeptides. Physical digestion - churning (muscular contraction & goblet cell). Gastric juice contains hydrochloric acid which kills harmful microorganisms and provides the optimum pH for protease enzymes.
• Oesophagus

  The tube leading from the mouth to the stomach. Has a sphincter muscle at the entrance to the stomach that relaxes to let food pass and contracts to close again.
• Small intestine


  Fats emulsified by bile, digested by pancreatic lipase. Starch broken down by pancreatic amylase. Proteins broken down by pancreatic proteases (trypsin) and peptidases. Sucrose broken down by sucrase.
• Pancreas


  Makes most of the digestive enzymes that are released into the duodenum in the form of pancreatic juice
• Liver


  Makes bile (alkaline) which is stored in the gallbladder, neutralises acid from stomach, emulsifies fats
• Large intestine


  Organ for absorption of minerals & vitamins, reabsorbing water from waste to maintain body's water levels
• Tooth structure


  Enamel, dentine, pulp, gum, cement, jawbone, blood supply
• Types of teeth


  • Incisors
  • Canines
  • Premolars
  • Molars