Exam question

• What structures in fish provide a large surface area for gas exchange?

  Gill filaments and lamellae
• How does the blood supply in bony fish affect gas exchange?

  It maintains a steep concentration gradient
• Why are the gills of bony fish thin?

  To reduce the diffusion pathway for gases
• What happens when the mouth of a fish opens?

  It lowers the buccal cavity, increasing volume
• What is the effect of increasing volume in the buccal cavity?

  It decreases pressure, forcing water in
• What ventilation mechanism do bony fish use to maximize oxygen uptake?

  Counter-current flow ventilation mechanism
• How does the counter-current flow mechanism work?

  Water and blood flow in opposite directions
• What is the benefit of the counter-current flow mechanism?

  It maintains a steep concentration gradient
• What type of gills do axolotls have?

  External gills
• How do axolotls ventilate their gills?

  By contracting body muscles/movement
• What is parallel flow in terms of fish respiration?

  Blood and water move in the same direction
• What is the maximum oxygen uptake efficiency of parallel flow?

  50% maximum of oxygen uptake
• How does the oxygen uptake of bony fish compare to parallel flow?

  Bony fish achieve 80% maximum uptake