Breathing

• Constantly breathing in and out


  Constantly new air coming in
• Concentration gradient of oxygen and carbon dioxide


  Moves blood through the capillaries
• When you exhale there is a greater percentage of carbon dioxide and a smaller percentage of oxygen
• Oxygen is needed for aerobic respiration and carbon dioxide is the waste gas
• Nitrogen is not used for respiration, so the percentage does not change
• Alveoli


  • Large surface area
  • Good blood supply in capillaries
  • One thick wall for short distance to increase the rate of diffusion
  • Mucus fluid lining the alveolus for gas to dissolve
• Gas exchange


  1. Oxygen goes from the air into the alveolus to haemoglobin in red blood cells

  2. Carbon dioxide goes from the blood plasma into the air in the alveolus
• Alveolus


  Air sack used for gas exchange
• The amount of inhaled air contains 21% of oxygen and 0.04% of carbon dioxide, while the air we breathe out contains 16.4% of oxygen and 4.4% of carbon dioxide
• This is because our cells use oxygen from the inhaled air to release energy and give out carbon dioxide as a byproduct
• Smoking increases the formation of plaque in blood vessels


  Chemicals in cigarette smoke cause the blood to thicken and form clots inside veins and arteries
• Cilia and goblet cells

  • Found in the trachea
  • Cilia beat backwards and forwards which sweep the mucus away from the lungs and towards the mouth
  • Mucus is made by goblet cells which traps dirt and bacteria
• As the activity level increases for someone


  Their energy requirement also increases
• If you are pregnant

  The energy needed increases because you are eating for 2 people to keep a balanced diet for both
• The woman is heavier

  She would need more energy to move
• Energy content of food experiment

  1. Heating the food

  2. Energy can be lost by heating the air

  3. Not fully burned piece of food

  4. Transfer time is longer
• Energy released per gram

  Mass of water (g) x temperature rise x 4.2 / mass of food sample
• Bomb calorimeter

  • Stirrer - distributes heat energy - heat transfer increases
  • Water inside the container - heat is trapped inside
  • Insulating container - heat is not given out
  • Food sample - is not on a needle
  • Oxygen-rich atmosphere around the food - encourages heat, heats faster
  • Ignition wires - lights food to give zero transfer time
• Health problems if you have saturated fats often

  • High cholesterol
  • High blood pressure
  • Obesity
  • Respiratory/mobility issues
• A person's breathing rate remains high after exercise

  They need to repay the oxygen debt
• During exercise you go into anaerobic respiration


  Lactic acid is created
• To break the lactate down


  You need oxygen to react with it
• Aerobic Respiration


  C6H1206 + 6O2—> 6CO2 + 6H20 (glucose + oxygen = carbon dioxide + water)
• Anaerobic respiration

  C6H12O6 —> 2C3H6O3 (glucose = lactic acid)
• Action during inhalation and exhalation

  External intercostal contract then relax. Internal intercostal muscles relax and then contract. Ribs move up and out then move down and in.

  diaphragm contracts then relaxes. The pressure in the thorax slightly drops and then raises slightly. the volume of air in lungs increases then decreases.
• Effects if smoking


  Carbon monoxide binds to haemoglobin in red blood cells which reduces the amount of oxygen carried in red blood cells. Tar is a carcinogen which causes cancer. Tar causes cells to mutate and divide rapidly. Smokers cough is caused by the mucus that now collects in the lungs. Bronchitis is when the lining of the bronchioles are swollen due to irritation from the smoke. This means that less air can reach the alveoli so less oxygen is transferred into the blood.
• ATP - adenosine triphosphate

  ATP delivers energy to places where it is needed (movement + nerve energy). produced by the mitochondria by aerobic respiration