Lungs and 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 sacks in the lungs called?

  Alveoli
• How are alveoli adapted for gas exchange?

  They have a large surface area and thin walls
• What is the significance of the thin walls of alveoli?

  They create a short diffusion pathway
• How many alveoli do adults typically have?

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

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

  To allow gases to dissolve for diffusion
• What color represents deoxygenated blood in the video?

  Blue
• How does oxygen diffuse into the blood from the alveoli?

  Down the concentration gradient
• How is carbon dioxide transported in the blood?

  It is dissolved in the blood plasma
• What happens to blood during gas exchange in the lungs?

  Deoxygenated blood enters, oxygenated blood leaves
• How does exercise affect breathing rate?

  It increases the breathing rate
• How do you calculate breathing rate?

  Breaths taken divided by 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
  • Short diffusion pathway
• 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 leaves the lungs
  4. Deoxygenated blood enters the lungs