11.2.1 Structure of the Respiratory System and Ventilation

• What is the process of exchanging gases in the lungs called?

  Breathing

  
• What is respiration in living organisms?

  A chemical process to release energy
• What is the pathway of air in the respiratory system?

  • Mouth
  • Trachea
  • Bronchi
  • Bronchioles
  • Alveoli

  
• What holds the lumen of the trachea open?

  Rings of cartilage
• Why is the trachea's shape a 'C'?

  To allow food to flow down the oesophagus

  
• What is the role of ciliated epithelium in the trachea?

  To clean the air before it reaches the lungs
• What do goblet cells produce?

  Sticky mucus
• What is the function of mucus in the respiratory system?

  To trap dust, dirt, and bacteria
• What are cilia in the respiratory system?

  Small hairs that push mucus up
• Where does gas exchange occur in the lungs?

  In the alveoli

  
• What are the features of alveoli that facilitate gas exchange?

  • Thin walls (one cell thick)
  • Large surface area
  • Moist surface
  • Rich blood supply
• Why are alveoli walls thin?

  To reduce the diffusion distance
• How does a large surface area benefit gas exchange?

  It maximizes exchange of gases
• Why is a moist surface important in alveoli?

  For dissolving gases to diffuse
• What maintains a concentration gradient in the alveoli?

  A rich blood supply
• What happens during inhalation (inspiration)?

  • External intercostal muscles contract
  • Diaphragm contracts and flattens
  • Thorax volume increases
  • Pressure inside decreases

  
• What occurs during exhalation (expiration)?

  • Intercostal muscles relax
  • Diaphragm relaxes and domes upwards
  • Thorax volume decreases
  • Pressure inside increases
• What do external intercostal muscles do during inspiration?

  Contract
• What do intercostal muscles do during expiration?

  Relax

  
• How does inhaled air compare to exhaled air?

  • Exhaled air has less oxygen
  • Exhaled air has more carbon dioxide
  • Exhaled air has more water vapor

  
• What instrument measures lung capacity?

  Spirometer

  
• What does a spirometer produce?

  A spirograph reading