Alveoli

• Why are there millions of alveoli

  It increases the surface area for gaseous Exchange
• What type of cells line the alveoli and what does this help with

  One cell layer thick lined with squamous epithelium that allows for easier diffusion
• A large what surrounds the alveoli?

  A large blood capillary network
• What do these capillaries consist of and what are they lined with?

  Lined by a single layer of endothelium. Consist of smaller arterioles (deoxygenated) and larger venues (oxygenated)
• Why are the capillaries narrow in diameter

  So that the Red blood cells can move in a single file
• What keeps the walls of the alveoli moist

  Tissue fluid
• The bronchioles end in...

  Infundibular (group of alveoli)