TRANSPORT WITHIN ANIMALS

• What do all animals have to transport substances around their bodies?

  Circulatory systems
• What are the main components of circulatory systems in animals?


  Blood vessels, a pump (the heart), and valves
• What is a double closed circulatory system?


  • Blood travels through the heart twice per circuit
  • Found in mammals
  • Delivers oxygenated blood to tissues faster than single circulatory systems
  • Maintains a better concentration gradient for substance exchange
• How many times does blood travel through the heart in a double circulatory system?


  Twice
• Why do double circulatory systems deliver oxygenated blood faster than single circulatory systems?


  Because blood travels through the heart twice per circuit
• How does a double circulatory system maintain a better concentration gradient?


  By allowing faster exchange of substances between blood and body cells
• What type of circulatory system do fish have?


  Single circulatory system
• How many times does blood travel through the heart in a single circulatory system?


  Once
• What are the characteristics of closed circulatory systems?


  • Blood flows through blood vessels
  • Requires a pump (the heart)
  • Found in fish and mammals
• In which organisms are closed circulatory systems found?


  Fish and mammals
• What type of closed circulatory system do fish have?


  Single closed circulatory system
• What type of closed circulatory system do mammals have?


  Double closed circulatory system
• What are the characteristics of open circulatory systems?


  • Blood flows freely throughout the body cavity
  • Found in insects
• In which organisms are open circulatory systems found?


  Insects
• What are venules?

  Small blood vessels that collect blood coming out of capillaries
• How does blood flow from capillaries to veins?

  Blood flows from capillaries into larger venules and then into veins
• What is the diameter range of venules?

  Around 7 micrometers to 1 millimeter
• What are arterioles?

  Smaller vessels that arteries split into when reaching an organ
• How can blood flow be controlled in arterioles?

  By contracting to restrict blood flow or relaxing to allow blood flow
• What is the primary function of arteries?

  To transport blood away from the heart to the organs
• What is a key feature of artery walls?

  They have thick layers of muscle
• Why do artery walls maintain high pressure?

  To ensure blood can be pumped around the body
• What role do elastic fibers play in artery walls?

  They allow the arteries to stretch
• What is the structure of the endothelium in arteries?

  It is folded, allowing the arteries to stretch
• What is the primary function of veins?

  To transport blood back to the heart
• How does the lumen of veins compare to arteries?

  The lumen of veins is wider than that of arteries
• What is the muscle wall structure of veins?

  They have a thin muscle wall and elastic tissue
• What is the purpose of valves in veins?

  To ensure blood flows towards the heart
• What do arterioles branch into?

  Very small vessels called capillaries
• What is the structure of capillary walls?

  Capillary walls are only one cell thick
• Why is the diffusion distance short between capillaries and body cells?

  Because capillaries pass very close to the body cells
• What is the significance of a short diffusion distance in capillaries?

  It allows for efficient exchange of substances
• What is tissue fluid?

  A combination of oxygen, water, and nutrients surrounding the cells
• What is pressure filtration?

  The process where substances move into tissue fluid from the capillaries
• What creates high hydrostatic pressure in capillaries?

  A high volume of blood being forced through narrow capillaries
• What happens to fluid in capillaries during pressure filtration?

  The fluid flows down the pressure gradient into the surrounding space
• What is created when fluid moves out of the capillaries?

  Tissue fluid is created
• What happens to hydrostatic pressure inside capillaries as fluid moves out?

  The hydrostatic pressure decreases
• What occurs to plasma proteins when fluid moves out of the capillaries?

  The plasma protein concentration inside the capillaries increases
• What is established when fluid moves out of the capillaries?

  A water potential gradient is established