What are the "twisty columns" and "rungs" in the DNA?
2 answers:
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<h2><u>Full Question:</u></h2>
In the alveolus pictured above, a disease or injury to which structures would reduce the ability of oxygen to diffuse from the alveolar space to the capillary?
A. A and B
B. B and C
C. B and D
D. A and D
<h2><u>Answer:</u></h2>The correct answer is option D.
<h3><u>Explanation:</u></h3>Alveoli is defined as the unicellular thickened sac like structure of lungs which helps in exchange of gases in lungs. The exchange membrane of lungs comprise of three structures -
A. The epithelium cells of Alveoli,
B. The basement membrane of alveolar epithelium,
C. The endothelial layer of blood capillary.
The red blood cells described here won't cause any problems to the diffusion of gases from alveolar cavity to blood. The structures mentioned here as the type 2 cells of Alveoli which secrete lecithin, a surfactant which releases the surface tension of Alveoli. This compound prevents the Alveoli from collapsing and helps in diffusion of gases. The other structure mentioned here as D are the alveolar epithelium which is the unicellular thickened membrane of Alveoli, helping in gaseous exchange.