exchange surfaces

• Why do multicellular organisms require specialized exchange surfaces?

  Because their surface area to volume ratio decreases as size increases.
• How do single-celled organisms exchange substances?

  They can easily absorb substances due to a short distance to cross.
• What is a key requirement for efficient gas exchange in multicellular organisms?

  Specialized exchange surfaces are needed for efficient gas exchange.
• What are two features of an efficient exchange surface?

  Large surface area and thin structure.
• Why is a good blood supply or ventilation important for exchange surfaces?

  It maintains a steep concentration gradient for gas exchange.
• What is the primary function of the lungs in mammals?

  To facilitate gas exchange with a large surface area.
• What role does the rib cage play in the respiratory system?

  It protects the lungs and aids in ventilation.
• What substance is secreted to reduce friction between the rib cage and lungs?

  A lubricating substance.
• What happens to the external intercostal muscles during inspiration?

  They contract to raise the rib cage.
• How does the diaphragm contribute to breathing?

  It contracts and flattens to increase thoracic volume.
• What is the difference in pressure that causes air to enter the lungs during inspiration?

  The pressure inside the lungs becomes lower than atmospheric pressure.
• What occurs during expiration in terms of muscle activity?

  The internal intercostal muscles contract while the external ones relax.
• What is a spirometer used for?

  To measure lung volume.
• What is vital capacity?

  The maximum volume of air that can be inhaled or exhaled in a single breath.
• What is tidal volume?

  The volume of air breathed in and out at rest.
• How is breathing rate calculated using a spirometer?

  By counting the number of peaks or troughs in a minute.
• What is residual volume?

  The volume of air always present in the lungs.
• What is inspiratory reserve volume?

  The additional volume of air that can be inhaled beyond tidal volume.
• What is expiratory reserve volume?

  The additional volume of air that can be exhaled beyond tidal volume.
• Why do fish require specialized exchange surfaces?

  Because they have a small surface area to volume ratio and an impermeable membrane.
• How many pairs of gills do bony fish have?

  Four pairs of gills.
• What is the function of lamellae in fish gills?

  They participate in gas exchange.
• How does counter current flow benefit fish during gas exchange?

  It maximizes the efficiency of oxygen uptake from water.
• What initiates the ventilation process in fish?

  Opening the mouth and lowering the floor of the buccal cavity.
• What role do spiracles play in insects?

  They allow direct transport of oxygen to tissues.
• What is the function of tracheal fluid in insects?

  It allows gases to dissolve and diffuse into cells.
• How do spiracles help insects manage water loss?

  They can be opened and closed to avoid excessive water loss.