gas exchange

Question 1

structure of alveoli and capillaries

Answer 1

• walls of squamous epithelium and are only one-celled thick
• this allows for gas exchange to occur quickly

Question 2

% of oxygen and carbon dioxide inspired

Answer 2

oxygen = 21%
carbon dioxide = 0.04%

Question 3

% of oxygen and carbon dioxide expired

Answer 3

oxygen = 16%
carbon dioxide = 4.3%

Question 4

characteristics of gas exchange

Answer 4

• a thin layer of moisture on the inside of alveoli
• constant breathing maintains a concentration gradient
• alveoli are one cell thick and have walls of squamous epithelium
• lungs are deep inside the chest cavity to stop the evaporation of moisture in the lungs

Question 5

what is gaseous exchange?

Answer 5

Air enters the alveoli when you breathe in. The capillaries receive deoxygenated blood from the artery to the lungs. Carbon dioxide diffuses from a high concentration in the blood to a low concentration in the alveolus. Oxygen diffuses from a high concentration in the alveoli into a low concentration in the bloodstream. The heart receives oxygenated blood from the capillaries.