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 thin cell layer and large surface area
• Why does the thin cell layer of alveoli increase diffusion rate?

  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 in the lungs?

  It gives up oxygen to the tissues
• What is the concentration gradient for oxygen in the alveoli?

  Higher in the alveoli than in blood
• 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
• What changes in breathing rate occur during exercise?

  Breathing rate increases
• How do you calculate breathing rate?

  Divide breaths taken 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
• Describe the process of gas exchange in the lungs.

  1. Deoxygenated blood enters capillaries.
  2. Oxygen diffuses from alveoli to blood.
  3. Carbon dioxide diffuses from blood to alveoli.
  4. Oxygenated blood leaves capillaries.