gas exchange

• What is gas exchange in organisms?

  It is the exchange of oxygen and carbon dioxide.

  
• Why is gas exchange vital for organisms?

  It provides oxygen for cellular respiration.

  
• What do some organisms lack for gas exchange?

  An open or closed circulatory system.

  
• What are the four properties of gas-exchange surfaces?

  • Size of the surface area
  • Moist surface
  • Thin membranes
  • Permeability & solubility of gases
• How does the size of the surface area improve gas exchange?

  It increases the area available for diffusion.
• Why is a moist surface important for gas exchange?

  It allows gases to dissolve for easier diffusion.
• How do thin membranes facilitate gas exchange?

  They shorten the diffusion pathway for gases.
• What role does permeability and solubility of gases play in gas exchange?

  They determine how easily gases can diffuse.
• What happens to the SA:V ratio as organisms increase in size?

  It decreases, making gas exchange more difficult.
• Why does the distance from the center of an organism to its exterior increase?

  As organisms grow larger, their volume increases.
• How do mammalian lungs differ from those of other animals?

  Mammalian lungs have unique structural adaptations.
• What do all mammals use for gas exchange?

  Lungs
• What is the function of the surfactant in alveoli?

  It reduces surface tension to prevent collapse.

  
• What are Type I and Type II pneumocytes?

  Type I cells are for gas exchange; Type II secrete surfactant.

  
• How does surfactant prevent alveolus collapse?

  It forms a monolayer on the alveolar surface.

  
• What is required for the diffusion of gases?

  Concentration gradients must be present.
• What is a concentration gradient?

  It is when particle concentration varies in different areas.
• How is the concentration of gases measured?

  As partial pressures (PO2 or PCO2).
• How is a high concentration gradient maintained in the alveoli?

  By continuous blood movement through capillaries.
• What does ventilation refer to?

  Movement of air into and out of the lungs.

  
• What are the two stages of ventilation?

  Inspiration and expiration.
• What muscles are involved in inhalation?

  Diaphragm and external intercostal muscles.

  
• What happens during exhalation?

  Diaphragm relaxes, rib cage moves downwards.

  
• How is lung volume measured?

  Using spirometers or lung volume bags.

  
• What is tidal volume?

  Normal volume of air breathed in or out.
• What is vital capacity?

  Total volume of air exhaled after maximum inhalation.

  
• What is inspiratory reserve volume (IR)?

  Air inhaled forcefully after normal inhalation.

  
• What is expiratory reserve volume (ER)?

  Air exhaled forcefully after normal exhalation.
• How can lung volumes be compared among different individuals?

  By measuring lung volumes in various conditions.

  
• What is the displacement method for measuring lung volume?

  Exhaling into an inverted vessel to measure water displacement.
• Why are alveoli important for gas exchange?

  They increase surface area and reduce diffusion distance.

  
• How does the surfactant in alveoli assist in gas exchange?

  It reduces surface tension, preventing collapse.

  
• How does vital capacity differ among individuals?

  It varies based on gender and height.

  
• What is the relationship between lung volume and exercise?

  Exercise can affect lung volumes and capacities.

  
• What is the role of capillaries in gas exchange?

  They increase surface area for diffusion of gases.
• How does the structure of alveoli facilitate gas exchange?

  They have thin walls and a large surface area.

  
• What happens to the concentration of oxygen in the blood during gas exchange?

  It increases as oxygen diffuses into the blood.

  
• What is the effect of breathing on carbon dioxide levels in the blood?

  Breathing out removes CO2 from the blood.

  
• How does the diaphragm contribute to ventilation?

  It contracts to increase thoracic volume during inhalation.

  
• What is the role of external intercostal muscles during inhalation?

  They lift the rib cage to expand the thorax.