If each human lung contains about 300 million alveoli with a summed total surface area for gas exchange of 40 square meters, what is the approximate surface area of a single alveolus?

Question

A.  0.133 square micrometers
B.  7.5 square micrometers
C.  750 square micrometers
D.  1.33 square micrometers
E.  133 square millimeters
F.  7.5 square millimeters

Clarify Question
  What is the key concept addressed by the question?
What type of thinking is required?
 
Gather Content
What do you already know about alveoli? What other information is related to the question?

Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
 
Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

A.  0.133 square micrometers

Clarify Question
  What is the key concept addressed by the question?
        · This question is asking you to calculate the surface area of an alveolus.
What type of thinking is required?
        · Analyze level:
            o This is an analyze question because you have to break alveoli and surface area into their component pieces to understand how they function.
 
Gather Content
What do you already know about alveoli? What other information is related to the question?
        · Alveoli are small sacs within the lungs that are surrounded by capillaries.
        · Alveoli are surrounded by capillaries, and provide the surface area over which gas exchange occurs.
 
Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
        · If the total surface area is 40 m2, and the number of alveoli is 300,000,000, the surface area of one alveolus is 40 m2/300,000,00 alveoli, which is 0.000000133 m2/alveolus.
        · 0.000000133m2 is equal to 0.133 micrometers.
 
Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        · Analyze level:
            o Answering this question correctly depended not only on distinguishing between alveoli and lungs, but on your ability to break down, or analyze, surface area. If you got an incorrect answer, did you remember that components of alveoli include their role as small units of function within the lung, or that their surface area is related to the surface area of the lungs? Did you have trouble breaking down the idea of surface area to determine the correct answer?