6.4 Gas Exchange
Define Gas exchange - correct answer ✔✔the exchange (diffusion) of oxygen and carbon dioxide to and
from the blood at the alveoli and the respiring tissues.
Define ventilation - correct answer ✔✔the movement of air into and out of the lungs in two stages:
inspiration and expiration. This is controlled by the movement of the diaphragm and ribcage.
State the location of gas exchange in humans - correct answer ✔✔internally, which allows for gas
exchange with the blood
Outline the mechanism of gas exchange in humans. - correct answer ✔✔in humans gas exchange occurs
in small air sacs called alveoli inside the lungs
Describe how the structure of the alveoli increases surface area for gas exchange. - correct answer
✔✔millions in number each with own netowkr of capillaries, membranes of alveoli and capillaries are
very thin so diffusion path is short, surfaces are wet so gasses are dissolved.
Outline the structure of type 1 pneumocytes. - correct answer ✔✔single layer of cells form the walls of
an alveolus, extremely thin - short diffusion distance, permeable - aids diffusion
Outline the structure and function of type II pneumocytes. - correct answer ✔✔secrete fluid to moisten
the inner surface of the alveolus, moisture allows oxygen in the alveolus to dissolve and then diffuse to
the blood in the alveolar capillaries, fluid contains surfactant to prevent the walls sticking together -
maintains the lumen, can divide to form Type I pneumocytes - repair damage
Describe two functions of the fluid secreted by type II pneumocytes. - correct answer ✔✔aids diffusion
of gases, contains surfactant to prevent the walls sticking together
Outline the flow of air into the lungs. - correct answer ✔✔the lungs in the trachea and bronchi and then
to the alveoli in bronchioles
Define Gas exchange - correct answer ✔✔the exchange (diffusion) of oxygen and carbon dioxide to and
from the blood at the alveoli and the respiring tissues.
Define ventilation - correct answer ✔✔the movement of air into and out of the lungs in two stages:
inspiration and expiration. This is controlled by the movement of the diaphragm and ribcage.
State the location of gas exchange in humans - correct answer ✔✔internally, which allows for gas
exchange with the blood
Outline the mechanism of gas exchange in humans. - correct answer ✔✔in humans gas exchange occurs
in small air sacs called alveoli inside the lungs
Describe how the structure of the alveoli increases surface area for gas exchange. - correct answer
✔✔millions in number each with own netowkr of capillaries, membranes of alveoli and capillaries are
very thin so diffusion path is short, surfaces are wet so gasses are dissolved.
Outline the structure of type 1 pneumocytes. - correct answer ✔✔single layer of cells form the walls of
an alveolus, extremely thin - short diffusion distance, permeable - aids diffusion
Outline the structure and function of type II pneumocytes. - correct answer ✔✔secrete fluid to moisten
the inner surface of the alveolus, moisture allows oxygen in the alveolus to dissolve and then diffuse to
the blood in the alveolar capillaries, fluid contains surfactant to prevent the walls sticking together -
maintains the lumen, can divide to form Type I pneumocytes - repair damage
Describe two functions of the fluid secreted by type II pneumocytes. - correct answer ✔✔aids diffusion
of gases, contains surfactant to prevent the walls sticking together
Outline the flow of air into the lungs. - correct answer ✔✔the lungs in the trachea and bronchi and then
to the alveoli in bronchioles
