Gas Exchange and Lungs

• What is the primary function of the lungs?

  To get oxygen from the air into blood
• Why do cells need oxygen?

  For cellular respiration to produce energy
• What is the trachea also known as?

  Windpipe
• 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 thin walls
• 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 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 carbon dioxide during gas exchange?

  It diffuses from blood into the alveoli
• What occurs continuously in the lungs?

  Gas exchange between blood and alveoli
• How can you calculate breathing rate?

  Divide breaths taken by time in minutes
• If you took 42 breaths in three 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 lungs.

  1. Oxygen diffuses from alveoli to blood
  2. Carbon dioxide diffuses from blood to alveoli
  3. Oxygenated blood is transported to the body
  4. Deoxygenated blood returns to the lungs
• What happens to breathing rate during exercise?

  • Breathing rate increases
  • More oxygen is needed for energy
• What is the role of hemoglobin in the blood?

  To carry oxygen to tissues
• How does physical activity affect the lungs?

  It increases the demand for oxygen