basic concepts
What is diffusion?
Movement of particles from high to low.
What are gills?
Structures for gas exchange.
What is ventilation?
Movement of air over surface.
What is a tracheal system?
Network of tubes for gas exchange.
What is abdominal pumping?
Rhythmic movement of tracheae.
Define gas exchange.
Exchange of oxygen and carbon dioxide.
What are lamellae?
Thin plates increasing surface area.
Describe how fish ventilate their gills.
By opening mouth and closing operculum.
Define spiracles.
Openings for air entry.
How do insects create a diffusion gradient?
by contracting and relaxing their abdominal muscles, pumping air in and out of the tracheal system.
What is surface area to volume ratio?
Ratio of surface area to volume.
What is countercurrent flow?
Water opposite to blood flow.
How do pressure changes allow water to enter a fish’s mouth?
Pressure changes in the mouth and opercular cavity cause water to flow over the gills. Mouth opens, pressure drops, water enters; mouth closes, pressure increases, pushing water over gills.
What is the role of tracheoles in gas exchange?
Delivers air directly to cells.
Explain how air reaches body cells in insects.
Diffusion along tracheoles.
Why is gas exchange important for organisms?
Provides oxygen for respiration.
How does countercurrent flow maximize gas exchange?
Maintains concentration gradient.
What is the role of the operculum in fish?
Covers and protects the gills.
How do insects control water loss through spiracles?
Opens and closes spiracles.
Why do active insects have more developed tracheal systems?
More oxygen for energy.
Why do larger organisms need specialized gas exchange systems?
Smaller surface area to volume ratio.
Explain how water flows over fish gills in one direction.
Water flows over gills in one direction, driven by mouth opening, closing, and the operculum moving, ensuring fresh water exposure.
Why is countercurrent flow more efficient than parallel flow?
Maintains high concentration gradient.
Why can’t larger animals use a tracheal system?
Insufficient surface area for exchange.
What role does lactic acid play in gas exchange in insects?
Reduces pH and triggers tracheal expansion.