Topic 11: Gas exchange

• Goblet cells: produces mucus
• The features of gas exchange surfaces in humans

  • large surface area
  • thin surface
  • good blood supply
  • good air ventilation
• Larynx: structure makes sounds
• Inhalation:

  • internal intercostal muscles: relaxes
  • external intercostal muscles: contracts, pulls up
  • diaphragm: contracts, flattens
  • volume of air in thorax: increase
  • pressure of thorax: decrease
  • ventilation of the lungs : air in
• Exhalation:

  • internal intercostal muscles: contracts
  • external intercostal muscles: relaxes
  • diaphragm: relaxes, return shape
  • volume of air in thorax: decrease
  • pressure of thorax: increase
  • ventilation of the lungs : air out
• What is the purpose of the C shaped cartilage rings?

  • help to keep the trachea open and to prevent it from collapsing during inhalation.

  
• What makes you breath in?

  The atmospheric pressure outside is higher and the pressure inside the lungs lower.

  The difference in pressure makes you to breath in and air will diffuse from high to low pressure region.
• Testing for Carbon dioxide?

  tested with limewater, if turns cloudy when Co2 is bubbled through it.
• Testing for Water Vapour?

  water vapour or water droplets turn cobalt chloride paper from blue to pink
• What happens during exercise?

  1. During exercise, the muscle cells respire more than they do at rest which means oxygen and glucose must be delivered to them more quickly and waste carbon dioxide must be removed more quickly.
  2. This is achieved by increasing the heart rate , rate of breathing and the depth of breathing.
  3. The increased heart rate increases the rate of blood flow around the body. The increased rate and depth of breathing increases the rate of gaseous exchange in the lungs.
  4. The muscles/liver store glucose as glycogen, this can be then converted back to glucose for use during exercise.
• Ribs: bones provide protection for the lungs.
• Bronchus: airway allows passage of air into lungs
• Trachea: airway allows passage of air into both lungs
• Diaphragm/ internal intercostal muscles: contracts to lower the ribcage
• External intercostal muscles: contracts of increase volume of thorax.
• Ciliated cells: sweeps away the mucus to back of the throat so that pathogens and dust particles can be swallowed and not entered into the lungs. This is to protect the breathing system from pathogens and particles.