Respiratory System

• Organs of the respiratory system

  • Nose
  • Pharynx
  • Larynx
  • Trachea
  • Bronchi
  • Bronchioles
  • Alveoli
  • Lungs
  • Diaphragm
• Nose/ nasal passage


  • Makes air moist as it passes inward
  • Traps bacteria carried in air currents using hairs(cilia)
• Trachea


  • Lined with rings of cartilage that support and hold it open
• Bronchi


  • Covered in rings of cartilage that hold them open
• Bronchioles


  • Numerous and very branched
  • Allow large amounts of air in and out of alveoli
• Alveoli


  • Site of gaseous exchange between air and blood
• Inspiration (breathing in)


  1. Intercostal muscles contract causing ribs to move up and out

  2. Diaphragm contracts and flattens

  3. Volume of chest increases

  4. Pressure in thorax decreases

  5. Air rushes in to fill lungs
• Expiration (breathing out)


  1. Intercostal muscles relax causing ribs to move down and in

  2. Diaphragm relaxes and returns to dome shape

  3. Pressure in thorax increases

  4. Air leaves the lungs
• Oxygen for respiration comes from the air inhaled into the lungs
• Waste products carbon dioxide and water are expelled through the lungs
• Respiration


  Process of 'burning' glucose using oxygen to release energy, producing carbon dioxide and water as waste
• Inhaled air contains more oxygen and less carbon dioxide than exhaled air
• Exercise increases the amount of CO2 exhaled
• Characteristics of alveoli that aid gaseous exchange

  • Thin walls to shorten diffusion distance
  • Moist lining to dissolve gases
  • Good blood supply to bring blood close to air
  • Large surface area
• Tobacco smoke contains over 4,000 chemicals, including many carcinogens and poisons
• Tar


  Particulate matter drawn into lungs when smoking, contains chemicals known to cause cancer
• Nicotine


  Highly addictive substance in cigarettes that makes the heart beat faster
• Carbon monoxide


  Poisonous gas in cigarette smoke that combines with haemoglobin, reducing oxygen transport
• Limitations of the bell jar model:

  • the diaphragm is flat before inhalation, not domed
  • the ribs don't move
  • there are no bronchioles
  • there is no alveoli, lungs are only represented by a balloon
• The respiratory system consists of the nose, pharynx, larynx, trachea, bronchi, bronchioles, alveoli and lungs.
• What is the quation for respiration

  Glucose+oxygen--> energy released+carbon dioxide+water
• CO2 limewater experiment

  before exercise breathe into literature time how long it gets cloudy,

  carry out exercise for 3 minutes and time again

  limewater turned cloudy more intensely after exercise. The reason is that during the exercise more respiration is occurring in our muscle cells and more CO2 is produced