AAMC 11 #143 bio explanation

[dragon mouse]

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Question:
In individuals suffering from pulmonary anthrax, the region of the thorax between the lungs is enlarged. Based on the passage, which of the following is most likely the reason for this enlargement?

Answer:
Swelling of the lymph nodes that receive lymph from the lungs

How is the lymph node swelling specific to pulmonary anthrax if the lymph nodes always converge there between the lungs? It might be because the lymph gathers up all the foreign debris or whatever, but I thought that the bacteria resist being gobbled up by the macrophages. Can someone clarify for me? I answered D (enlargement of alveolar sacs because of increased macrophage activity), reasoning that because the macrophages initially there were not able to eat the bacteria, even more macrophages were recruited to help out.

 

[Rabolisk]

The answer cannot be D because alveolar sacs are not in between the lungs. They are part of the lungs.

 

[dougkaye]

Swollen lymph nodes near the infection should be recognized as an answer/question that is testing your understanding of the nonspecific immune response to infection, where inflammation is probably the most telltale sign, followed by fever. As to why the lymph nodes swell up, you should be familiar with this once you review immune system again.