Arteries, veins, capillaries

• What is the function of valves in blood vessels?

  To prevent backflow of blood
• What type of blood do arteries carry?

  Oxygenated blood (except pulmonary artery)
• How does the size of the lumen affect blood pressure in arteries?

  It maintains high blood pressure
• What is the wall structure of arteries?

  Thick, elastic, muscular wall
• Why can arterial walls stretch?

  To cope with high blood pressure
• What type of blood do veins carry?

  Deoxygenated blood (carbon cells)
• What is the size of the lumen in veins?

  Large with very low blood pressure
• What is the wall structure of veins?

  Thin, less muscular wall
• Why do veins have valves?

  To prevent backflow of blood
• What is the size of the lumen in capillaries?

  Very small
• Do capillaries have valves?

  No, they have none
• What is the wall structure of capillaries?

  One layer of epithelium cells
• Why do capillaries have a thin wall?

  To allow faster diffusion of gases and nutrients
• What type of blood do capillaries transport?

  Oxygenated going to cells, deoxygenated coming from cells
• What are the main differences between arteries, veins, and capillaries?

  • Arteries:
  • Thick, elastic, muscular walls
  • Carry oxygenated blood (except pulmonary artery)
  • Small lumen, high blood pressure

  
  

  • Veins:
  • Thin, less muscular walls
  • Carry deoxygenated blood
  • Large lumen, very low blood pressure
  • Have valves to prevent backflow

  
  

  • Capillaries:
  • Very small lumen
  • No valves
  • One layer of epithelium cells
  • Allow faster diffusion of gases and nutrients