Blood Vessels and Blood

• What are the three types of blood vessels?

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

  Carry blood away from the heart
• Why do arteries have thick muscle and elastic layers?

  To withstand high blood pressure
• What do capillaries do?

  Carry blood close to body cells
• What is the structure of capillary walls?

  Thin and permeable to allow diffusion
• What is blood classified as?

  A tissue
• What are the four components of blood and their functions?

  • Red blood cells: Carry oxygen
  • White blood cells: Defend against infection
  • Platelets: Help blood clot at wounds
  • Plasma: Carries nutrients and waste
• What is the function of red blood cells?

  Carry oxygen around the body
• What is unique about the structure of red blood cells?

  They have no nucleus for more oxygen
• What shape do red blood cells have and why?

  Biconcave shape for a big surface area
• What is the role of haemoglobin in red blood cells?

  It binds to oxygen
• What is the function of white blood cells?

  Defend against infection
• What do white blood cells produce?

  Antibodies and antitoxins
• What is the function of platelets?

  Help blood to clot at a wound
• What does plasma carry in the blood?

  Amino acids, glucose, urea, and proteins
• What is the function of veins?

  Carry blood back to the heart
• What feature do veins have to prevent backflow?

  Valves inside
• Why do veins have thinner walls than arteries?

  Because blood pressure is lower
• How does the structure of arteries differ from veins?

  Arteries have thick walls; veins have thinner walls
• What is the relationship between blood flow rate and time taken?

  Rate of blood flow = volume / time taken