The Breathing System

When you breath in, your ribcage moves up and your diapragm down

When you breath out, your ribcage moves down and your diapragm up

RIBCAGE= protects organs in the thorax (upper half of your main body)

DIAPHRAGM= sheet of muscle which separates your thorax from your abdomen

• In through mouth
• Down trachea
• Down bronchi
• Down bronchioles
• Into alveoli (air sacs in the lungs)
  

Alveoli are adapted really well for the diffusion of oxygen into the blood and the diffusion of waste carbon dioxide into the lungs for disposal.

• Create a large surface area for diffusion (there are millions of alveoli in your lungs!)
• Moist
• Thin walls mean less distance for substances to travel
• Very close to capillaries- good access to blood for diffusion
• The movement of the blood and the constant breathing of the lungs keeps the concentration gradient high and so perfect for diffusion