Chapter 1

• Respiration

  A chemical reaction which occurs in every one of the cells in the human body, releasing energy stored in glucose
• Aerobic respiration


  Glucose + oxygen -> carbon dioxide + water
• Aerobic respiration


  • Slowly releases lots of energy stored in glucose
  • Occurs in the mitochondria found in the cytoplasm
• Gas exchange


  1. Oxygen from the air moves into the blood

  2. Carbon dioxide from the blood moves into the air
• Blood in the capillaries

  Contains only a small amount of oxygen and a lot of carbon dioxide
• Diffusion


  The movement of particles in the air from an area of high concentration to an area of low concentration
• Oxygen moving into the blood

  Dissolves and combines with haemoglobin to form oxyhaemoglobin
• Ventilation


  The process of breathing
• Inhalation


  1. Diaphragm contracts and moves downwards

  2. Intercostal muscles contract and move ribs upwards and outwards

  3. Increases lung volume and reduces pressure, causing air to move in
• Exhalation


  1. Diaphragm relaxes and moves upwards

  2. Intercostal muscles relax and move ribs downwards and inwards

  3. Decreases lung volume and increases pressure, causing air to move out
• Structures air passes through

  • Nose/Mouth
  • Trachea (windpipe)
  • Bronchus
  • Bronchioles
  • Alveoli
  • Lungs
• Structures air moves out of

  • Lungs
  • Alveoli
  • Bronchioles
  • Bronchus
  • Trachea (windpipe)
  • Nose/Mouth
• Plasma


  The liquid that makes up more than half of the blood, mainly water and pale yellow in colour, conveys substances around the body
• Red blood cells


  • Most numerous cell in the body
  • Made in bone marrow
  • Contain haemoglobin to bind and carry oxygen
  • No nucleus or mitochondria to maximise oxygen carrying capacity
  • Biconcave shape to maximise surface area for oxygen absorption
• White blood cells


  • Part of the immune system
  • Made in bone marrow
  • Phagocytes engulf and kill pathogens
  • Antibodies stick to and kill pathogens directly