Blood vessels

• What are the three types of blood vessels in the body?

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

  To carry blood away from the heart
• What do arteries contain to help them function?

  Thick layers of muscle and elastic fibres
• Why are artery walls strong and elastic?

  To withstand high pressure from the heart
• How does the lumen of arteries compare to their wall thickness?

  The walls are thick compared to the lumen
• What is the role of capillaries in the circulatory system?

  • Exchange materials at tissues
  • Supply oxygen and nutrients to cells
  • Remove waste products like carbon dioxide
• What is a key characteristic of capillaries?

  They have permeable walls
• Why are capillary walls usually only one cell thick?

  To increase the rate of diffusion
• How does the narrowness of capillaries affect diffusion?

  It increases the surface area for diffusion
• What happens to capillaries as they connect to veins?

  They join up to form veins
• What is the primary function of veins?

  To carry blood to the heart
• Why do veins have thinner walls than arteries?

  Blood is at lower pressure in veins
• How does the lumen of veins compare to that of arteries?

  Veins have a bigger lumen than arteries
• What feature do veins have to ensure blood flows in the correct direction?

  Valves to prevent backflow
• What is the purpose of calculating the rate of blood flow?

  To understand how blood circulates