Blood Vessels

• What are the three main types of blood vessels?

  Arteries, veins, and capillaries
• How does the structure of blood vessel walls relate to their function?

  The structure supports their specific functions
• What tough fibrous protein is found in the walls of arteries and veins?

  Collagen
• What is the role of elastic fibers in blood vessels?

  They allow vessels to stretch and recoil
• What function do smooth muscle cells serve in blood vessels?

  They allow vessels to constrict and dilate
• What are the three layers of an artery wall?

  1. Endothelium
  2. Thick layer of smooth muscle and elastic tissue
  3. Outermost layer with collagen fibers
• What is the function of the endothelium in arteries?

  It reduces friction of blood flow
• Why is the muscle layer thick in arteries?

  To withstand high pressure
• How does elastic tissue help maintain blood pressure in arteries?

  By stretching and recoiling
• What is the lumen of an artery like?

  Narrow
• What causes a pulse in arteries?

  Stretching from increased blood volume
• What do veins return to the heart?

  Blood
• Why is blood pressure in veins very low?

  They receive blood from capillary networks
• How does the smooth muscle and elastic layer in veins compare to arteries?

  It is much thinner in veins
• What aids blood flow in veins?

  Skeletal movement
• What is the lumen like in veins?

  Wider
• What do veins contain to prevent backflow?

  Valves
• What is the wall of a capillary made of?

  A single layer of endothelial cells
• Why is the capillary wall structure important?

  It reduces diffusion distance for gases
• What are the gaps in capillary walls called?

  Pores
• What do the pores in capillary walls allow?

  Blood plasma to leak out
• What is the diameter of a capillary lumen like?

  Very narrow
• How do white blood cells combat infection in tissues?

  By squeezing through capillary pores
• Why are capillaries narrow?

  To allow red blood cells to squeeze
• What is the benefit of capillaries being highly branched?

  It provides a large surface area for diffusion
• What blood vessel carries deoxygenated blood away from the heart?

  Pulmonary artery
• What blood vessel carries deoxygenated blood to the heart?

  Vena cava
• What blood vessel carries oxygenated blood?

  Pulmonary vein
• What is the term for blood that is rich in oxygen?

  Oxygenated blood
• What is the term for blood that is low in oxygen?

  Deoxygenated blood
• What is the term for blood that contains carbon dioxide?

  Deoxygenated blood
• What is the term for blood that is rich in nutrients?

  Nutrient-rich blood
• What are the three main types of blood vessels?

  Arteries, veins, and capillaries
• How does the structure of blood vessel walls relate to their function?

  Their structure supports their specific functions
• What tough fibrous protein is found in the walls of arteries and veins?

  Collagen
• What is the role of elastic fibers in blood vessels?

  They allow vessels to stretch and recoil
• What function do smooth muscle cells serve in blood vessels?

  They allow vessels to constrict and dilate
• What are the three layers of an artery wall?

  1. Endothelium
  2. Smooth muscle and elastic tissue
  3. Outermost collagen layer
• What is the function of the endothelium in arteries?

  It reduces friction of blood flow
• Why is the smooth muscle layer thick in arteries?

  To withstand high pressure