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admin
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 Posted: Mon Jul 09, 2007 12:54 am Post subject: |
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| You are exactly correct. In the back of your mind, you very likely understand the consequence of Experiments 1 and 2 but those experiments don't directly investigate the resulting effect on the immune system thus they do not comprise the correct response. |
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admin
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| Posted: Mon Aug 06, 2007 10:42 pm Post subject: |
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Your conclusion is incorrect primarily for the 2 following reasons:
(1) you said that:
| Quote: | | 90% of the cells in the lymphatic tissue ( . . . ) is populated by the thymus |
Which is not the same as what Experiment 1 suggested which is that 90% of the radiolabeled cells from the thymus ended up in lymphatic tissue. This is very, very different. Those cells represent almost all the cells from the thymus but, for all we know, they may only represent 1% of all of the cells in lymphatic tissue. There is nothing in Experiment 1 that gives us any understanding as to how important those specific cells would be in the lymphatic system.
(2) Now let's pretend that something in Experiment 1 went so far as to say that indeed those thymus cells represented a very large percentage of the cells in the lymphatic tissue, would that be enough to "directly" conclude that the immune system would be compromised without the thymus? Still insufficient information! An alcoholic's liver will only fail after 90% of it has been damaged (same with the pancreas). There are rare patient's who are born with 90% less brain matter than the average member of the population but they have normal intellectual function. You still would need evidence, like Experiment 3, that links thymus cells to immune function directly.
I can understand why you made your conclusion. You would be correct if it were Verbal Reasoning where you might be looking for an inference. But these are experiments in science and you are asked for direct evidence. |
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admin
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| Posted: Tue Jul 28, 2009 12:23 pm Post subject: |
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Experiment 2 would be correct IF: it had compared to groups in which both underwent thymectomies and then we gauged their immune function in vivo (in the organism). Instead, "thymus cells" were removed. This does not constitute a thymectomy.
Also, cells were grown outside of the organism and that is certainly suggestive (ie. the fact that no T cells grew in the younger rats) but it is not conclusive evidence about the need for the thymus in vivo. But certainly, the first paragraph above is the stronger argument for why Experiment 2 is not correct. |
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