Respiratory system

• Respiration


  Chemical reactions controlled by enzymes to release energy from glucose
• Respiration takes place all the time in all living things (plants, animals, bacteria & fungi)
• A lot of energy is released from glucose & it is used to make lots of ATP
• Aerobic respiration

  Glucose + oxygen -> carbon dioxide + water
• Aerobic respiration takes place in mitochondria
• Anaerobic respiration

  Glucose -> lactic acid
• Aerobic respiration

  Produces more ATP, releases more energy
• Anaerobic respiration

  Produces less ATP, releases less energy
• Fresh peas are alive

  Carry out respiration & release heat energy, increasing temperature
• Boiled peas are dead

  Don't respire, so don't release heat, so temperature stays the same
• The peas should be disinfected to kill bacteria that would also carry out respiration
• Nicotine

  • Addictive substance in cigarette smoke & increases blood pressure
• Tar

  • Carcinogen (chemical that causes cancer) & is linked to lung cancer
• Carbon monoxide

  • Binds haemoglobin in red blood cells & reduces oxygen carrying capacity
• Bronchitis

  • Cigarette smoke paralyses cilia so they can't brush mucus that traps dust & bacteria away, causing inflammation (swelling)
• Emphysema

  • Tar causes alveoli walls break down, decreasing surface area to absorb oxygen
• Oxygen debt


  People breathe more heavily to take in more oxygen to break down lactic acid
• Emphysema 


  Tar causes alveoli walls break down, decreasing surface area to absorb oxygen
• Bronchitis 


  Cigarette smoke paralyses cilia so they cant brush mucus that traps dust and bacteria away, causing inflammation (swelling )
• Capillary

  Tiny blood vessel where gas exchange takes place
• Alveoli

  Microscopic air sacs in the lungs where gas exchange takes place
• Inspired air contains 21% oxygen
• Expired air contains 16% oxygen
• Expired air contains 4% carbon dioxide
• Expired air contains 79% nitrogen
• Oxygen decreases in expired air as it is used in respiration
• Carbon dioxide increases in expired air as it is produced in respiration
• Limewater turns cloudy when carbon dioxide is bubbled through it
• Sodium hydroxide absorbs carbon dioxide but doesn't test for it
• Water levels in expired air are always high because the lungs are moist
• Trachea


  Tube that air passes through from the mouth to the bronchi
• Bronchi


  Takes air from the trachea into each lung
• Bronchioles


  Small tubes that air passes through throughout the lungs
• Alveoli


  Air sacs in the lungs where gas exchange takes place
• Ribs


  Bones protecting the lungs which also move to enable ventilation
• Intercostal muscles


  Muscles in-between the ribs which contract to move the ribs during ventilation
• Diaphragm


  Sheet of muscle underneath the lungs which moves during ventilation
• Bell jar model vs lungs differences

  bell jar no intercostal muscles, diaphragm needs to be pulled down not flat, balloon doesnt fill space
• Inspired air contains 79% nitrogen
• Inspired air contains 0.04% carbon dioxide