Gas Exchange

• What is the primary function of the lungs in humans?

  Gas exchange
• What gas is taken in by the lungs from the air?

  Oxygen
• What waste product is released by the lungs?

  Carbon dioxide
• How are the lungs structured to facilitate gas exchange?

  They provide efficient exchange of gases
• Through which pathways does air enter the lungs?

  Through the mouth and nose
• What does the trachea split into?

  Two bronchi
• What are the small air sacs in the lungs called?

  Alveoli
• What is the role of alveoli in the lungs?

  They are the exchange surface for gases
• What separates the lungs from the rest of the body?

  The diaphragm
• What surrounds the lungs for protection?

  Pleural membranes and rib cage
• What causes ventilation in the lungs?

  Contraction and relaxation of muscles
• What are the steps of inhalation?

  • External intercostal muscles contract
  • Rib cage moves up and out
  • Diaphragm contracts and flattens
  • Volume increases, pressure decreases
  • Air is drawn into the body
• What are the steps of exhalation?

  • External intercostal muscles relax
  • Rib cage moves down and in
  • Diaphragm relaxes and moves upwards
  • Volume decreases, pressure increases
  • Air is expelled from the body
• What is the definition of ventilation?

  Movement of air in and out of lungs
• How are alveoli adapted for gas exchange?

  They allow efficient diffusion of gases
• What type of blood is pumped to the lungs for oxygenation?

  Deoxygenated blood
• Why does deoxygenated blood have high carbon dioxide levels?

  It has supplied oxygen to respiring cells
• What happens to oxygen in the alveoli?

  It diffuses into the blood
• What happens to carbon dioxide in the alveoli?

  It diffuses out of the blood
• What occurs after blood is oxygenated in the lungs?

  It returns to the heart
• Why does oxygen diffuse into respiring cells?

  Concentration of oxygen is greater in blood
• What is produced as a waste product of respiration?

  Carbon dioxide
• How does carbon dioxide move into the blood from respiring cells?

  By diffusion down the concentration gradient
• What happens to the blood after it becomes deoxygenated?

  The cycle repeats