Circulatory System- Blood Vessels

• In what direction do arteries carry blood?

  Away from the heart
• What is the function of the capillaries?

  Used for exchanging materials in tissues
• Where do veins carry blood?

  To the heart
• Why are artery walls strong and elastic?

  Because the heart pumps blood at high pressure
• What is the hole of blood vessels called?

  The lumen
• How thick are capillary walls?

  One cell thick
• How do capillaries walls make diffusion easier?

  They make diffusion distance shorter
• Do veins have a large or small lumen?

  A large lumen
• Do veins carry blood at a lower or higher blood pressure than arteries?

  Lower
• Which blood vessel contains valves?

  Veins