The lower airway ends at the Alveoli, gas exchange occurs at this level. Oxygen moves to the hemoglobin by passing through a semipermible membrane. Name this membrane.

The lower airway ends at the Alveoli, gas exchange occurs at this level. Oxygen moves to the hemoglobin by passing through a semipermible membrane. Name this membrane.
A . Capillary bed
B . Bronchioles
C . Capillary blood
D . Veinule

View Answer

Answer: A

Explanation:

The bronchi sub divide into smaller and smaller passages, they end with tiny air sacs called alveoli. The alveoli are covered in capillaries, this is where the gas exchange occurs. The carbon dioxide moves off of the hemoglobin and oxygen moves to the hemoglobin by diffusion. Movement of a gas from a higher concentration to a lower concentration. At the level of the capillaries is where the arteries switch to veins, capillaries are so small only one blood cell can pass through at a time.