gas exchange

• What is the main function of the lungs?

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

  The heart pumps blood to the lungs
• What is the tube called that air passes into the lungs through?

  Trachea
• What prevents the trachea from collapsing when we inhale?

  Rings of cartilage
• What do the bronchi split into?

  Bronchioles
• What are the tiny air sacs in the lungs called?

  Alveoli
• What is the role of alveoli in the lungs?

  Sites of gas exchange
• How do gases diffuse in and out of the bloodstream in the alveoli?

  Oxygen diffuses in, carbon dioxide diffuses out
• What is the first adaptation of alveoli for gas exchange?

  Millions of alveoli provide a huge surface area
• Why do alveoli have very thin walls?

  To shorten the diffusion path
• What ensures a good blood supply to the alveoli?

  Rapid removal of oxygen from blood
• How does breathing affect gas exchange?

  It increases the rate of diffusion
• What does breathing bring into the alveoli?

  Fresh oxygen
• What does breathing take away from the alveoli?

  Carbon dioxide
• Why is it important to learn the adaptations of the lungs?

  They are frequently tested in exams
• What are the adaptations of alveoli for gas exchange?

  • Millions of alveoli for large surface area
  • Very thin walls for short diffusion path
  • Good blood supply for rapid oxygen removal
  • Breathing increases concentration gradients
• What are specialized exchange surfaces?

  Parts of an organism for substance exchange
• What is the main purpose of specialized exchange surfaces?

  To exchange substances with the environment
• What are the main specialized exchange surfaces in humans?

  Alveoli and Villi
• What is the function of alveoli?

  To exchange oxygen and carbon dioxide
• Where are alveoli located?

  At the ends of the bronchioles
• What do Villi do in the small intestine?

  Help absorb nutrients like glucose
• What specialized exchange surface do plants have for water absorption?

  Root hair cells
• What is the role of leaves in plants regarding gas exchange?

  To absorb carbon dioxide from the air
• What are the common features of specialized exchange surfaces?

  • Large surface area
  • Very thin surfaces
  • Permeable to exchanged substances
  • Good blood supply
  • Good supply of external medium
• Why is a large surface area important for exchange surfaces?

  It allows more molecules to diffuse simultaneously
• How do alveoli increase their surface area?

  By having hundreds of millions of them
• Why are exchange surfaces usually very thin?

  To reduce the diffusion distance for substances
• What does it mean for exchange surfaces to be permeable?

  They allow substances to diffuse across
• How does a good blood supply benefit exchange surfaces?

  It maintains a concentration gradient
• What is the role of the external medium in exchange surfaces?

  To provide substances for absorption
• Why do we need a good supply of air in alveoli?

  To maintain a high concentration of oxygen
• What are the five main features of specialized exchange surfaces?

  1. Large surface area
  2. Very thin surfaces
  3. Permeable to exchanged substances
  4. Good supply of blood
  5. Good supply of external medium
• What is the purpose of breathing in relation to alveoli?

  To ensure a good supply of air
• How does a good blood supply help with glucose absorption in Villi?

  It quickly replaces absorbed glucose with fresh blood
• How do the features of exchange surfaces relate to their functions?

  They enhance the efficiency of substance exchange
• describe a feature of gills to increase rate of diffuison

  gills have many projections for a larger surface area