Gas Exchanges in Human

• cartilage (in trachea)

  prevents the trachea from collapsing in on itself during the absence of air & protects it by keeping open
• Ribs

  protects vital organs and blood vessels & allows for efficient breathing by expanding & contracting
• intercostal muscles 


  situated between the ribs that create and move the chest wall

  (inhaling) internal: relaxes

  (inhaling) external: contracts
• diaphragm

  produces volume & pressure changes in the thorax leading to the ventilation of the lungs
• what happens to the external intercostal muscles when you inspire (breathe in)

  the muscles contract and it pulls the ribcages upwards & outwards
• what happens to the external muscles when you expire (breathe out)

  the muscles relaxes & allows the ribcage downwards & inwards
• pressure in the thorax

  inspiration: ATM pressure > pressure in thorax

  expiration: ATM pressure < pressure in thorax
• what happens to the diaphragm when you inspire

  muscles contract & the diaphragm moves downwards & the volume of the thorax increases
• what happens to the diaphragm when you expire

  muscles relax & the diaphragm increases & thorax volume decreases
• ciliated cells 


  have cilia (little hairs) that sweep back & forth in coordinated ways to brush mucus up the lungs & into the mouth
• mucus & cilia

  goblet cells produce sticky mucus to trap & eliminate particular matters & microorganisms
• effect of increased physical activity

  tissues respire at a higher rate, change in breathing volume & rate helps keeps CO2 and pH levels safe
• spirometer 


  measures the amount of air you can breathe out in 1 sec or the total volume of air you can exhale in one forced breathe