Fish

• How do fish extract oxygen?

  From water
• What is the oxygen content in air?

  20.9%
• What is the oxygen content in water?

  Approx 0.8%
• Why do fish need to pass large volumes of water over their gills?

  To extract sufficient oxygen from low water content
• How much oxygen can fish extract from water passing through their gills?

  As much as 80%
• What are the three reasons fish can extract high levels of oxygen from water?

  1. Large surface area for gas exchange
  2. Short diffusion distance across gill membranes
  3. High concentration gradient between blood and water
• What covers the gills of fish?

  Operculum
• How do active fish maintain water flow through their gills?

  By keeping their mouths open while swimming
• What is the structure that supports gill filaments?

  Bony gill arch
• What is the function of gill lamellae?

  They facilitate gas exchange
• What is the significance of the short diffusion distance in fish gills?

  It allows for efficient oxygen transfer
• What is countercurrent exchange in fish gills?

  Blood and water flow in opposite directions
• How does countercurrent exchange maintain the concentration gradient?

  It allows oxygen-rich water to meet oxygen-poor blood
• What is the problem with parallel flow in fish gills?

  It does not maintain the concentration gradient
• What happens when blood that is well loaded with oxygen meets water?

  Diffusion of oxygen from water to blood occurs
• What is the maximum percentage of oxygen absorbed in a parallel flow system?

  About 50%
• What are the differences between countercurrent and parallel flow systems in fish gills?

  Countercurrent flow:

  • Blood and water flow in opposite directions
  • Maintains concentration gradient
  • Higher oxygen absorption

  
  

  Parallel flow:

  • Blood and water flow in the same direction
  • Does not maintain concentration gradient
  • Lower oxygen absorption
• What are the smallest projections in the gill called?

  Lamellae
• Why are fish gills red in color?

  Due to a rich blood supply
• What additional feature do highly active fish have?

  They swim with their mouths open
• What is the role of gill rakers?

  To filter food particles from water
• How does the structure of gill filaments aid in gas exchange?

  They provide a large surface area
• What is the significance of the blood vessel carrying oxygenated blood away from the gills?

  It distributes oxygen throughout the body
• What is the function of the gill bar?

  To support the gill structure
• How does the flow of water affect gas exchange in fish?

  It maintains a continuous supply of oxygen
• What is the relationship between water flow and blood flow in fish gills?

  Water flows opposite to blood flow
• What is the role of gill filaments in gas exchange?

  They increase the surface area for diffusion
• How does the structure of gill lamellae contribute to gas exchange?

  They are thin and delicate for efficient diffusion
• How does the oxygen concentration in water affect fish respiration?

  Lower oxygen concentration requires more water flow
• What happens to oxygen levels in water as it passes over gills?

  Oxygen levels decrease as it diffuses into blood
• Why is it important for fish to have a high rate of oxygen absorption?

  To support their metabolic needs
• What is the primary function of fish gills?

  Gas exchange
• How does the design of fish gills optimize oxygen extraction?

  Through large surface area and countercurrent flow
• What is the significance of maintaining a concentration gradient in fish gills?

  It maximizes oxygen diffusion into the blood
• How does the oxygen concentration in blood change as it passes through the gills?

  It increases as oxygen diffuses from water
• What is the role of blood vessels in gill lamellae?

  To transport oxygenated blood
• What adaptations do fish have for efficient gas exchange?

  Gills with large surface area and thin membranes