ventilation of the human lungs

• what is the defintion of inspiration


  the act of air being drawn into the lungs
• what is meant by expiration


  the act of releasing air from the lungs
• what happends to the external intercostal muscles and ribs druing inspiration


  the muscle contract raising the ribs up and out
• what happends to the external intercostal muscles and ribs druing expiration


  the muscles relax movign the ribs down and in
• what happens to the outer pleural membrane during inspiration


  it is pulled outwards reducing the pessure in the pleural cavity
• what happens to the outer pleural membrane during expiration


  it moves inwards
• what happens to the inner pleural membrane druring inspiration


  it is pulled outwards
• what happens to the inner pleural membrane druring expiration


  it moves inwards
• what happens to the lungs and alvioli during inspiration


  the lung surface is drawn out causing the alvioli to expand
• what happens to the lungs and alveoli during expiration


  the lungs move in and the alveoli deflate
• what happens to the pressure in the alveoli during inspiration


  it is lower than the atmosphere presure so air will move in
• what happens to the pressure in the alveoli during expiration


  it is higher than the atmosphere pressure so air will move out