Alveoli and gas exchange

Where are the alveoli located in the lungs?

• At the beginning of the trachea

• In the main bronchi

• At the very end of the bronchioles

• Within the vocal cords

What happens to oxygen after it diffuses across the alveolar and capillary cell membranes?

• It is immediately exhaled.

• It binds with hemoglobin in red blood cells.

• It converts into carbon dioxide.

• It is stored in the alveoli.

How is a constant concentration gradient maintained for efficient gas exchange in the alveoli?

• By the moist lining of the alveoli.

• By the large surface area of the alveoli.

• By continuous supply of oxygen through breathing and removal by blood flow.

• By the presence of hemoglobin in red blood cells.

What feature of the alveoli's lining helps provide a short diffusion pathway for gases?

• It has a large surface area.

• It is only one cell thick.

• It has a moist lining.

• It is surrounded by a dense capillary network.