lungs and gas exchange

• What is the primary function of the lungs?

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

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

  The windpipe
• What happens to air after it passes through the trachea?

  It divides between the two bronchi and further into bronchioles
• What are the small sacs in the lungs called?

  Alveoli
• How are alveoli adapted for gas exchange?

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

  It creates a short diffusion pathway for gases
• 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 walls of alveoli moist?

  To allow gases to dissolve and increase their rate of diffusion
• What happens to hemoglobin in red blood cells when it reaches the lungs?

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

  Higher in the alveoli than in the blood
• How does carbon dioxide move during gas exchange?

  It diffuses from the blood into the alveoli
• How is carbon dioxide transported in the blood?

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

  Deoxygenated blood enters the capillaries and oxygenated blood leaves
• How can you calculate your breathing rate?

  By dividing the number of breaths taken by the 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 very thin cells
  • Large surface area (hundreds of millions)
  • Moist walls for gas dissolution
  • Short diffusion pathway
• 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