lungs

• what occurs in the lungs?

  gas exchange
• capillary's are...

  1 cell thick
• why are capillaries 1 cell thick?

  to allow for gas exchange
• what is gas exchange?

  the means by which we get oxygen from the air into our blood.
• explain stage 1 of the path taken by oxygen

  air is breathed through trachea
• explain stage 2 of the path taken by oxygen

  air passes down through bronchi to the bronchioles
• explain stage 3 of the path taken by oxygen

  air moves into alveolus
• explain stage 4 of path taken by oxygen

  oxygen dissolves in the moist lining and diffuses through the 1 cell thick wall
• explain stage 5 of path taken by oxygen

  oxygen diffuses into red blood cell and combines with haemoglobin to form oxyhaemoglobin
• name the type of glands that release hormones into the bloodstream

  endocrine
• in what form is oxygen transported by red blood cells

  oxyhaemoglobin