Blood vessels

• What are the three main types of blood vessels?

  Arteries, capillaries, and veins
• What is the primary function of arteries?

  To carry blood away from the heart to the organs
• Why do arteries have high pressure?

  Because they carry blood away from the heart
• What structural features of arteries help maintain high pressure?

  Muscular walls and elastic fibers
• What is the lumen size of arteries like?

  Small lumen
• What is the function of capillaries?

  To bring blood to the cells of the body
• How do substances move in and out of capillaries?

  Through diffusion
• What is the thickness of capillary walls?

  Very thin, just one cell thick
• Why are capillary walls so thin?

  To allow easy diffusion of substances
• What is the primary function of veins?

  To carry blood from the organs back to the heart
• What is the pressure like in veins?

  Low pressure
• What structural features of veins assist in blood flow?

  Thin walls and larger lumen
• What is the purpose of valves in veins?

  To prevent backflow of blood
• What are the key differences between arteries, capillaries, and veins?

  • Arteries: carry blood away from the heart, high pressure, muscular walls, small lumen
  • Capillaries: bring blood to cells, very thin walls (one cell thick), allow diffusion
  • Veins: carry blood back to the heart, low pressure, thin walls, larger lumen, valves to prevent backflow