1.7 Absorption of Materials

• In animals, how are substances like oxygen and carbon dioxide exchanged at the cellular level between the blood and tissues?

  By capillary networks.
• factors which makes the villi great at absorbing materials

  - large surface area

  - thin lining, for easy diffusion of molecules

  - extensive blood supply
• What is the organ of gas exchange in animals?

  The lungs.
• Where in the lungs are gases exchanged?

  At the alveoli. (air sacs)
• What is the organ of nutrient absorption in animals?

  The small intestine.
• Where in the small intestine are nutrients absorbed?

  At the villi (singular villus)
• Where do glucose and amino acids go when absorbed through the villi walls?

  Into the capillary network.
• the lacteal transports....

  
  

  fatty acids and glycerol