The blood vessels

• What is one of the functions of the circulatory system in humans?

  To transport substances
• What are the three types of blood vessels in the circulatory system?

  • Arteries
  • Veins
  • Capillaries
• What do arteries do?

  Carry blood away from the heart
• What do veins do?

  Transport blood to the heart
• What are capillaries?

  Tiny blood vessels where exchange of materials occurs
• How does blood flow through the circulatory system?

  Blood is pumped from the heart in arteries and returned in veins
• What is the role of capillaries in the circulatory system?

  To connect arteries and veins and allow exchange of molecules
• What is the lumen in blood vessels?

  The channel that carries blood
• What type of blood do arteries carry?

  Oxygenated blood, except for the pulmonary artery
• What type of blood do veins carry?

  Deoxygenated blood, except for the pulmonary vein
• Why do arteries have thick muscular and elastic walls?

  To pump and accommodate blood under high pressure
• Why do veins have thin walls?

  Because they carry blood under low or negative pressure
• What is the function of connective tissue in arteries?

  To provide strength
• How does the lumen size differ between arteries and veins?

  Arteries have a narrow lumen, while veins have a wide lumen
• What is diffusion in the context of capillaries?

  The process where particles spread from a region of higher concentration to a region of lower concentration
• What gas diffuses through the capillary wall into tissue fluid?

  Oxygen
• What is carbon dioxide in relation to respiration?

  A by-product of respiration
• What happens to glucose in the circulatory system?

  It diffuses from blood plasma to tissue fluid and then to cells
• What is urea?

  A nitrogenous waste product resulting from the breakdown of proteins
• How does urea move in the circulatory system?

  It diffuses from liver cells to tissue fluid and then into blood plasma
• What is the role of the liver in relation to blood?

  It processes substances absorbed by the digestive system
• What is the significance of the capillary walls being one cell thick?

  It allows for efficient exchange of molecules between blood and cells
• What are the differences between arteries, veins, and capillaries?

  • Arteries: Carry blood away from the heart, thick walls, narrow lumen, oxygenated blood (except pulmonary artery)
  • Veins: Carry blood to the heart, thin walls, wide lumen, deoxygenated blood (except pulmonary vein)
  • Capillaries: Connect arteries and veins, one cell thick walls, allow exchange of materials