Chapter 5: Gas Exchange

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    Created by
    Aarush Sanghavi

    Cards (10)

    • The Gaseous Exchange System
      The Diagram
    • Ventilation 

      Differences in air pressure caused by breathing
      Intercostal muscles (external and internal) and diaphragm
    • Inhalation (Breathing in)

      External intercostal muscles contract
      Internal intercostal muscles relax
      Raise ribs upwards and outwards
      The diaphragm contracts and flattens
    • Pressure when inhaling
      The volume inside thorax increases → pressure inside thorax decreases
      Atmospheric pressure > pressure inside thorax
      Air moves into the lungs
      Lungs inflate
    • Exhalation (Breathing out)
      External intercostal muscles relax
      Internal intercostal muscle contract
      Lower ribs downwards and inwards
      Muscle in the diaphragm relaxes
      The diaphragm bulges up due to pressure from organs below
    • Pressure when exhaling
      The volume inside thorax decreases → pressure inside thorax increases
      The pressure inside thorax > atmospheric pressure
      Air forced out of lungs
    • Gas Exchange in Unicellular Oxygen
      Rely on Diffusion alone
    • Diffusion definition
      Net movement of molecules or ions, from a place with a higher concentration to a place with a lower concentration down a concentration gradient as a result of random movement
    • Gas Exchange in larger organisms
      Require a Gas exchange system
      Gas exchange takes place in alveoli
    • How does Gas Exchange happen
      When air is inhaled close inhalationThe action of breathing in., oxygen diffuses from the alveoli into the blood to be used for respiration by the body's cells.