blood vessels

• Arteries


  Carry blood away from the heart
• Arterioles


  Smaller than arteries, branch off from arteries
• Capillaries


  Connect arterioles to veins, one cell thick
• Veins


  Carry blood back to the heart
• Blood vessel network


  1. Arteries

  2. Arterioles

  3. Capillaries

  4. Veins
• Artery wall


  • Thicker muscular layer
  • Thicker elastic layer
• Vein wall


  • Thinner muscular layer
  • Thinner elastic layer
  • Contain valves
• Capillary


  • One cell thick
  • Slow blood flow to allow diffusion
• Arteriole


  • Thicker muscular layer than arteries
  • Thinner elastic layer than arteries
• Arteries do not have valves
• Capillaries do not have muscular or elastic tissues
• Capillaries form a network or bed, not just a single capillary