Transport

• What are capillaries?

  Smallest blood vessels for material exchange
• What is the primary function of capillaries?

  Efficient exchange of materials between blood and tissues
• What are the adaptations of capillaries for material exchange?

  • Large surface area from branching
  • Thin walls (one cell thick)
  • Permeable walls for gases and nutrients
  • Fenestrations for rapid exchange
  • Small lumen for slow blood flow
• How do capillaries achieve a large surface area?

  Through extensive branching and narrow diameters
• How thick are capillary walls compared to other blood vessels?

  Very thin, only one cell thick
• Are capillary walls permeable or impermeable?

  Permeable
• What are fenestrations in capillaries?

  Small pores allowing rapid exchange of larger molecules
• What is the lumen size of capillaries compared to their size?

  Small diameter
• What is the direction of blood flow through arteries to veins?

  Artery -> Arteriole -> capillary bed -> Venule -> vein
• What do arteries do with blood?

  Carry blood away from the heart
• Why do arteries have thick walls?

  To withstand high pressure
• What is the lumen size of arteries relative to their wall thickness?

  Small lumen relative to wall thickness
• What do veins do with blood?

  Carry blood toward the heart
• Why do veins have thinner walls?

  They carry blood under low pressure
• What is the lumen size of veins relative to their wall thickness?

  Large lumen relative to wall thickness
• What feature prevents backflow of blood in veins?

  Valves
• What are the adaptations of arteries for high blood pressure transport?

  • Thick muscle layer for regulation
  • Elastic tissue for stretching and recoiling
  • Small lumen to maintain high pressure
• What two layers are thicker in arteries than in veins?

  Muscle layer and elastic tissue layer
• How does the muscle layer help maintain blood pressure in arteries?

  Contracts to regulate blood flow
• How does elastic tissue help maintain blood pressure in arteries?

  Allows arteries to stretch and recoil
• How does a small lumen help maintain blood pressure in arteries?

  Reduces space blood flows through
• What is pulse rate?

  Number of heartbeats per minute
• Where can you find the carotid pulse?

  In the neck
• Where can you find the radial pulse?

  In the wrist
• How do you calculate pulse rate from beats in 10 seconds?

  Multiply by 6
• How do you calculate pulse rate from beats in 15 seconds?

  Multiply by 4
• How do you calculate pulse rate from beats in 20 seconds?

  Multiply by 3
• How do you calculate pulse rate from beats in 40 seconds?

  Multiply by 1.5
• How do you calculate error in pulse rate calculations?

  Error = (Estimated - Actual) / Actual * 100%
• What are the adaptations of veins for low pressure blood return?

  • Valves to prevent backflow
  • Thin, flexible walls for compression
  • Large lumen to reduce resistance
• What do valves in veins do?

  Prevent backflow of blood
• How do thin, flexible walls of veins aid blood flow?

  Allow compression by skeletal muscles
• How does a large lumen help blood flow in veins?

  Reduces resistance to blood flow
• What is coronary artery occlusion?

  Blockage of arteries supplying heart muscle
• What are the causes of coronary artery occlusion?

  Atherosclerosis and blood clots
• What are the consequences of coronary artery occlusion?

  Reduced blood flow leading to angina or heart attack
• What is transpiration in plants?

  • Loss of water vapor from stomata
  • Pulls water up through xylem vessels
  • Driven by tension created by transpiration
• What is the name of the vessels that transport water in plants?

  Xylem vessels
• What creates the tension that pulls water up in plants?

  Transpiration from the leaves
• What property of water allows it to be pulled up in a stream?

  Cohesion of water molecules