lungs & gas exchange

• 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 branches that air travels through after the bronchi called?

  Bronchioles
• What are alveoli compared to in the study material?

  Bunches of grapes
• What is the structure of alveoli?

  One layer of very thin cells
• Why is the thin cell layer in alveoli important?

  It creates a short diffusion pathway
• How many alveoli do adults have approximately?

  Hundreds of millions
• What would happen if all alveoli were spread out flat?

  They would cover half a tennis court
• Why are the walls of alveoli moist?

  To allow gases to dissolve for diffusion
• What happens to hemoglobin in red blood cells when it reaches the lungs?

  It has given up much of its oxygen
• What is the concentration gradient for oxygen in the alveoli?

  Higher in alveoli than in blood
• How does carbon dioxide diffuse in the lungs?

  From blood to alveoli due to gradient
• How is carbon dioxide transported in the blood?

  Dissolved in blood plasma
• What happens 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 is 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 are the key features of alveoli that facilitate gas exchange?

  • One layer of thin cells
  • Large surface area
  • Moist walls for gas dissolution
• What happens to breathing rate during exercise?

  • Breathing rate increases
  • More oxygen is needed for energy
  • Carbon dioxide removal is enhanced