respiratory system

• The breathing/Respiratory system

  A) Nose

  B) Trachea

  C) Bronchus

  D) Bronchiole

  E) Alveoli

  F) Intercoastal muscles

  G) Ribs

  H) Diaphragm

  I) Left Lung

  
• INHALATION/INSPIRATION

  Intercoastal muscles contracts and ribcage moves up and out

  Diaphragm muscle contracting and diaphragm flattens

  As the volume of the thorax increases, lung and thoracic pressure decreases. Air rushes into the lungs through the trachea and the elastic lungs expand to fill up this extra space and equalise pressure
• Intercoastal muscles relax and ribcage moves down and in. Diaphragm relaxes and becomes dome shaped. As the volume of the thorax decreases, lung and thoracic pressure increases. Air is squeezed out of the lungs
• Bell jar - similarities

  • The bell jar is roughly the same shape as the ribcage
  • The balloons inflate and deflate like the lungs
  • The rubber sheet can be moved and made into a dome shape like the ribcage
• Bell jar - differences

  • The bell jar is solid and cant move like the ribcage can. The space inside the bell jar is filled with air but in the thorax it is fluid filled
  • There is a large space around the balloons in the bell jar but in the thorax it is small. Balloons have no alveoli so less surface area than in the lungs
  • When breathing in (inhalation) the rubber sheet in pulled downwards below the bell jar but in the thorax, diaphragm flattens
• To improve on the bell jar you could get bigger balloons, fill balloons with sponges to mimic alveoli
• Alveoli

  Air breathed in contains more oxygen that the blood arriving at the alveolus. Oxygen dissolves in the moist lining of the alveolus. Oxygen diffuses into the blood, down the concentration gradient, through the thin alveolus wall. Blood carries the oxygen away so the concentration gradient is maintained. Blood in the capillaries arriving at the alveolus contains more CO2 than the air in the alveolus. CO2 diffuses into the alveolus to be expired
• Alveoli adapted to their function for gas exchange?

  Millions of alveoli - large surface area for increased gas exchange by diffusion

  1 cell thick wall - short diffusion distance for easier gas exchange

  Moist lining - gases dissolve in moisture for easier diffusion

  Lots of capillaries - blood moves oxygen away from the exchange surface and CO2 towards it, maintaining the diffusion gradient, speeding up diffusion.
• Goblet cell - produces sticky mucus , dust/bacteria gets caught in the mucus

  Ciliated cell - ciliated cell cilia moves mucus and any trapped particles upwards to the throat and out of the lungs. It is then swallowed

  A) cilia

  B) mucus

  C) ciliated cell

  D) goblet cell

  
• cartilage rings in the walls of the trachea help keep the trachea open
• Pathway of gas through the respiratory system: nose → trachea → bronchi → bronchioles → alveoli → capillaries