topic 3

• What is the relationship between surface area and volume in organisms?

  Larger organisms have a lower surface area to volume ratio
• Why do small organisms like amoeba not need special adaptations for gas exchange?

  They have a large surface area compared to volume
• What is a key adaptation for larger organisms regarding gas exchange?

  They require adaptations for mass transport
• What are some key adaptations for gas exchange in different organisms?

  • Villi and microvilli in small intestines
  • Alveoli and bronchioles in mammals
  • Spiracles and tracheae in terrestrial insects
  • Gill filaments and lamellae in fish
  • Stomata in plants
• What is the scientific term for breathing?

  Ventilation
• What is the difference between breathing and respiration?

  Breathing is air movement; respiration is energy release
• What are the key structures of the human gas exchange system?

  Alveoli, bronchioles, bronchi, trachea, lungs
• What muscles are involved in human ventilation?

  Diaphragm and intercostal muscles
• What does the term antagonistic mean in muscle function?

  One muscle contracts while the other relaxes
• What happens to the diaphragm during inhalation?

  It contracts and moves downwards
• What occurs to the thorax volume during inhalation?

  The volume of the thorax increases
• What is the pulmonary ventilation calculation?

  Tidal volume times ventilation rate
• What is the unit for pulmonary ventilation?

  Decimeters cubed per minute
• What is the role of alveoli in gas exchange?

  They facilitate diffusion between air and blood
• How many alveoli are in each lung?

  Around 300 million
• Why do terrestrial insects have a tracheal system?

  To facilitate ventilation and gas exchange
• What is the function of spiracles in insects?

  They allow gases to enter and exit
• What is the counter current flow mechanism in fish gills?

  Water flows opposite to blood in capillaries
• What adaptations do fish gills have for gas exchange?

  Large surface area, short diffusion distance
• What is the role of stomata in leaves?

  They allow gas exchange for photosynthesis
• When do stomata typically close?

  At night when it's dark
• What is the palisade mesophyll's role in leaves?

  It is where photosynthesis mainly occurs
• What happens to stomata during the day?

  They open to allow gas exchange
• What is the significance of the thin alveolar epithelium?

  It minimizes diffusion distance for gases
• How do insects maintain a steep concentration gradient for gas exchange?

  By using oxygen and producing carbon dioxide
• What is the role of capillaries in gill lamellae?

  They provide a short diffusion distance
• What is the primary function of the tracheal system in insects?

  To deliver oxygen to respiring cells
• What happens to the volume of the thorax during exhalation?

  The volume of the thorax decreases
• What is the effect of diaphragm relaxation during exhalation?

  It causes the diaphragm to dome upwards
• What is the significance of the waterproof exoskeleton in terrestrial insects?

  It prevents water loss during gas exchange
• How do fish maintain a concentration gradient for gas exchange?

  By constantly moving water over their gills
• What is the role of the spongy mesophyll in leaves?

  It contains air spaces for gas exchange
• What is the purpose of the gill lamellae in fish?

  To increase the surface area for gas exchange
• What is the primary function of the trachea in insects?

  To transport air to the tracheal system
• What happens to the concentration gradient in concurrent flow?

  Equilibrium is reached, stopping diffusion
• What is the role of the abdominal muscles in insect ventilation?

  They help move gases in and out of the tracheal system
• What is the significance of the large number of tracheae in insects?

  They provide a large surface area for gas exchange
• How do stomata help in photosynthesis?

  They allow carbon dioxide to enter the leaf
• What happens to stomata during the night?

  They close to prevent water loss
• What is the role of the palisade mesophyll in photosynthesis?

  It is the main site for photosynthesis