Blood and circulation

• What is the primary function of the lungs in the circulatory system?

  Gas exchange
• How does blood collect oxygen in the lungs?

  The heart pumps blood to the lungs where it collects oxygen
• What are the two main tubes that air passes into the lungs through?

  The trachea
• What is the function of the cartilage in the trachea?

  It prevents the trachea from collapsing when we inhale
• What do the bronchi subdivide into?

  Bronchioles
• What are alveoli?

  Tiny air sacs where gas exchange occurs
• What is the significance of the large number of alveoli in the lungs?

  They provide a huge surface area for gas exchange
• Why do alveoli have very thin walls?

  To shorten the diffusion path for gases
• How does a good blood supply in the alveoli aid gas exchange?

  It rapidly removes oxygen, maintaining a steep concentration gradient
• How does breathing affect the rate of diffusion in the lungs?

  It brings fresh oxygen in and removes carbon dioxide, enhancing concentration gradients
• What are the adaptations of the alveoli for gas exchange?

  • Millions of alveoli provide a large surface area
  • Very thin walls for short diffusion path
  • Good blood supply to maintain concentration gradients
• What type of circulatory system do humans have?

  A double circulatory system
• Where does blood collect oxygen in the circulatory process?

  In the lungs
• What happens to blood after it collects oxygen in the lungs?

  It returns to the heart and is pumped around the body
• What do arteries carry from the heart?

  Very high pressure blood to the organs
• What is the first adaptation of arteries that helps them function?

  They have very thick muscular walls
• Why do arteries need thick muscular walls?

  To withstand the very high pressure of the blood
• What happens to blood in the arteries with each heartbeat?

  It surges through the arteries
• What can be felt in the wrist as blood surges through the arteries?

  The pulse
• What do elastic fibers in arteries do?

  They stretch and recoil to keep blood moving
• What are capillaries responsible for in the circulatory system?

  Allowing substances to diffuse between blood and cells
• What substances diffuse from the blood to the cells in capillaries?

  Glucose and oxygen
• What diffuses from the cells back to the blood in capillaries?

  Carbon dioxide
• Why do capillaries have very thin walls?

  To allow for a short diffusion pathway
• What happens to blood after it passes through the organs?

  It makes its way back to the heart through veins
• What is a problem with blood traveling back to the heart through veins?

  It travels slowly under low pressure
• Why do veins have thin walls?

  Because the blood pressure is low
• What do many veins contain to assist blood flow?

  Valves
• What is the function of valves in veins?

  To stop blood from flowing backwards
• What happens to the valves when blood flows in the correct direction?

  The valves open to allow blood to flow through
• What happens to the valves when blood starts to flow backwards?

  The valves shut
• What are the key structural features of arteries, veins, and capillaries and their functions?

  • Arteries: Thick muscular walls, elastic fibers for high pressure blood transport
  • Capillaries: Thin walls for rapid diffusion of substances
  • Veins: Thin walls, valves to prevent backflow of low pressure blood
• What are the main components of the human circulatory system?

  • Heart
  • Arteries
  • Veins
  • Capillaries
• What should you be able to describe by the end of the video on the heart structure?

  The structure of the heart and how it pumps blood around the body
• What is the circulatory system in fish like?

  • Single circulatory system
  • Deoxygenated blood is pumped to the gills
  • Blood collects oxygen and becomes oxygenated
  • Oxygenated blood goes to the organs
  • Blood returns to the heart
• What is a disadvantage of a single circulatory system in fish?

  Blood loses pressure as it passes through the gills, traveling slowly to the organs
• How does the double circulatory system in humans work?

  • Deoxygenated blood is pumped to the lungs
  • Blood collects oxygen in the lungs
  • Oxygenated blood returns to the heart
  • Heart pumps oxygenated blood to the organs
  • Blood transfers oxygen to body cells
• What is the benefit of a double circulatory system?

  It allows blood to travel rapidly to tissues, delivering oxygen efficiently
• What are the four chambers of the human heart?

  • Left atrium
  • Right atrium
  • Left ventricle
  • Right ventricle
• What separates the atria from the ventricles in the heart?

  Valves