lungs & gas exchange

• What is the primary function of the lungs?

  To get oxygen from the air into the bloodstream
• What is the trachea also known as?

  The windpipe
• Why do all cells need oxygen?

  For the process of cellular respiration
• What happens to air after it passes through the trachea?

  It divides between the two bronchi
• What are the small sacks in the lungs called?

  Alveoli
• How are alveoli adapted for gas exchange?

  They have a large surface area and a thin cell layer
• How many alveoli do adults have approximately?

  Hundreds of millions
• What is the significance of the alveolar walls being moist?

  It allows gases to dissolve, increasing their rate of diffusion
• What is the concentration gradient for oxygen in the alveoli?

  Higher in the alveoli than in the blood
• How is carbon dioxide transported in the blood?

  It is dissolved in the blood plasma
• What happens to deoxygenated blood in the lungs?

  It enters the capillaries to receive oxygen
• What changes occur in breathing rate during exercise?

  Breathing rate increases
• How do you calculate breathing rate?

  Divide the number of breaths taken by the time in minutes
• If you took 42 breaths in 3 minutes, what is your breathing rate?

  14 breaths per minute
• What are the key features of alveoli that facilitate gas exchange?

  • One layer of thin cells
  • Large surface area
  • Moist walls for gas dissolution
• Describe the process of gas exchange in the alveoli.

  1. Oxygen diffuses from alveoli to blood (higher concentration in alveoli).
  2. Carbon dioxide diffuses from blood to alveoli (higher concentration in blood).
  3. Oxygenated blood leaves the lungs, while carbon dioxide is exhaled.