This is the question, asked nine days ago: A man of 100 kg, what will be the masses of his living human cells, dead human cells, extracellular matrix/matrices, bacteria, and the remainder?

As I have continued to research the question it has become apparent that I haven't been able to find out even what is the mass of the ECM of the heart, nor that of any other organ. The reason may be that the word "mass" is too common a word, with other senses as in "a large mass of tissue". Or it may be that this aspect is not of interest to biologists (and quite hard to measure?), and the ECM has not caught the attention of popularizers of science until very recently. I mean, the amount of each element in the periodic table the body is well publicized.

Whatever the reason, I am thinking that maybe I should ask a smaller, easier question, such as, what is the mass of ECM in the heart, or what is the percentage of ECM by mass in any organ. Would this go down well with Biology.SE, and if it would, would it be okay to keep the hard question, or would the new question get flagged as a duplicate.

I suspect that if (as I would quite like to do, and might seem logical) in the hope of getting an answer to at least one of them, I posted separate questions for the mass of the ECM of the brain, the kidneys, the liver, the heart, the biceps muscle, and so on, someone will object. But if I made a question asking for the ECM mass of ANY organ, I would be flagged as asking for a list, right?

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    $\begingroup$ Yeah, I think it's not a very well-defined question. What counts as ECM mass vs cellular mass, when some of the ECM is directly connected to cells and all is somewhat connected. With all the tissues of the body it's really dozens or hundreds of sub questions and I can't see anyone being sufficiently interested to go through it all. Then the issue of bacterial cells is yet another separate issue. Focusing on one tissue and just one distinction probably makes better sense. $\endgroup$
    – Bryan Krause Mod
    Commented Sep 19, 2021 at 17:21
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    $\begingroup$ I think from a biologist's perspective this mostly feels like "trivia", though. It's certainly important to think about the ECM, and I don't think this is some sort of new revelation, but I also don't see the point of setting it on a scale. Mass isn't a particularly useful way to understand functions of different aspects of a biological tissue. $\endgroup$
    – Bryan Krause Mod
    Commented Sep 19, 2021 at 17:24
  • $\begingroup$ @BryanKrause Does the question get brownie points here for being a question about biology that would interest the layman. I mean, laymen are telling each other that we are seventy percent water (it's what I heard). That also is probably of no scientific significance. Likewise the percentages of each element in the body, but again, it fascinates the layman. $\endgroup$ Commented Sep 19, 2021 at 18:11
  • $\begingroup$ Don't really want to start a debate or discussion with you because I don't find this very interesting, but both the water and elemental percentages seem to me both more biologically relevant and also far far more straightforward to measure. They'd also make pretty poor questions here without some support for why it was relevant to ask them. $\endgroup$
    – Bryan Krause Mod
    Commented Sep 19, 2021 at 22:24
  • $\begingroup$ Coming from a non-biologist, I also agree that this question feels like trivia: interesting to know, but doesn't look really useful. Like, why should I know how many kg of bacteria do I have? $\endgroup$
    – Andrew T.
    Commented Sep 20, 2021 at 13:14
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    $\begingroup$ @BryanKrause "Don't really want to start a debate or discussion with you because I don't find this very interesting, but[...]". Do you mean you don't want me to respond to your comment? $\endgroup$ Commented Sep 20, 2021 at 15:44
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    $\begingroup$ @AndrewT. Do you mean your are a non-biologist, or that I am, or something else? I thought that SE was a place that layman could come to ask interesting questions (including "trivial pursuits" type questions that are mainly of interest to the layman). Is Biology off limits to nonbiologists to some extent? $\endgroup$ Commented Sep 20, 2021 at 15:50
  • $\begingroup$ @MatthewChristopherBartsh I meant that I'm a non-biologist, and it's only my personal evaluation of the question. Nonbiologists are certainly welcome on this site, but there's no guarantee that all kinds of questions are welcome, considering that the tooltip for upvote & downvote also mentions the usefulness. $\endgroup$
    – Andrew T.
    Commented Sep 20, 2021 at 16:08
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    $\begingroup$ @AndrewT. "“It is good that we all now have a better estimate to quote,” says Peer Bork, a bioinformatician at the European Molecular Biology Laboratory in Heidelberg, Germany, who works on the human and other complex microbiomes. “But I don’t think it will actually have any biological significance.”" says nature.com/articles/nature.2016.19136 and so I am puzzled at your attitude. Even Nature has devoted an entire article to something that they themselves say has no biological significance. How do you explain that? $\endgroup$ Commented Sep 20, 2021 at 16:10
  • $\begingroup$ @AndrewT. By "tooltip" do you mean guidelines? Where can I read about the tooltip and/or guidelines for asking questions at Biology? $\endgroup$ Commented Sep 20, 2021 at 16:16
  • $\begingroup$ @MatthewChristopherBartsh "How do you explain that?" I can't and won't answer that, but I'll just give an example on another SE site that some questions are not welcome even if they may be interesting: Is non-mainstream physics appropriate for this site?. Regarding the tooltip, it's when you hover the mouse cursor on the upvote & downvote buttons. $\endgroup$
    – Andrew T.
    Commented Sep 20, 2021 at 16:28
  • $\begingroup$ @AndrewT. Thanks for the useful info. BTW your name sometimes sometimes is displayed by the system with a space and sometimes without. $\endgroup$ Commented Sep 20, 2021 at 16:35
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    $\begingroup$ @MatthewChristopherBartsh Responding is fine, but I think the argument about whether it's interesting isn't one we're likely to come to agreement on. The reason the # of bacteria thing was in Nature is because it's a long running myth and no one had really measured it well except for some old envelope estimate that got propagated. "There's a lot of bacteria living on and in a multicellular animal" is interesting, useful biology. Estimating the precise numbers or mass involved may not be. $\endgroup$
    – Bryan Krause Mod
    Commented Sep 20, 2021 at 19:32
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    $\begingroup$ @MatthewChristopherBartsh just my opinion - the question is way too long and there is too many meandering parts; If you’d asked me just a week ago etc and it reads like a blog post. Cut it down to exactly what's necessary and you'll have a better chance of getting answer :) $\endgroup$
    – user438383
    Commented Sep 21, 2021 at 12:18
  • $\begingroup$ @I have done as you suggested, to some extent. I cut out most of the intro. jakebeal suggested something similar. I also deleted everything related to bacteria, and everything else not related to the ECM. $\endgroup$ Commented Sep 22, 2021 at 16:47

1 Answer 1


I would suggest that your question can be improved by focusing it on what it is that you are actually trying to learn by means of asking this question.

As with many things in biology, there are fuzzy areas where definitions aren't clear, such as "what exactly counts as extracellular?" This fuzziness diffuses the focus of the question and makes it harder to answer effectively.

As such, I would suggest you approach this as a series of questions where you focus on specific aspects of interest to you. For example, it seems like the ECM is of primary interest, so what is it that you're really trying to learn about it? Something like "how much ECM is there in our bodies"? Then don't constrain the measurement to mass, but see what people think is a good way of quantifying ECM.

Focusing a question generally doesn't mean adding more qualifiers: that often just makes it less likely that an answer will be available. Rather, it is often better done by clarifying the context and purpose behind the question, such that a reader can tell clearly whether an answer is actually sufficient to address it.

  • $\begingroup$ This is very good advice contrasting the focus that is needed to improve a question with the type of focus that isn't actually that helpful. $\endgroup$
    – Bryan Krause Mod
    Commented Sep 21, 2021 at 14:43
  • $\begingroup$ Upvoted. I edited the question according to your suggestion. Your final paragraph contains much food for thought. $\endgroup$ Commented Sep 22, 2021 at 16:21
  • $\begingroup$ Definitely better, but I still think you could cut most of the introduction if you want to have it be more focused. $\endgroup$
    – jakebeal
    Commented Sep 22, 2021 at 16:26
  • $\begingroup$ @jakebeal I deleted about fifty-one percent of the introduction. I think it is an improvement. Regarding " I would suggest you approach this as a series of questions where you focus on specific aspects of interest to you. ", when you say "a series", do you mean I should wait for the first question to be answered or closed or whatever before asking the next question (e.g. "How much/many "dead human cells" is/are there in the human body") or should I ask all of them in quick succession, or some other schedule? $\endgroup$ Commented Sep 22, 2021 at 16:44
  • $\begingroup$ @MatthewChristopherBartsh Personally, when I ask I tend to go one at a time, since the answer to the first is likely to affect my posing of the next. $\endgroup$
    – jakebeal
    Commented Sep 22, 2021 at 16:59
  • $\begingroup$ I was thinking of asking a new question ("How much ECM is there in the heart") without deleting the existing one. My hope is that this is an easier question than "How much ECM is there in the body?". What are your thoughts? $\endgroup$ Commented Oct 6, 2021 at 20:50
  • $\begingroup$ Scratch that, I asked it as a question: biology.meta.stackexchange.com/q/4237/65518 . No one has answered, and about three have viewed my question about how much ECM there is in the body. What is likely to happen to it, and what can I do, and why does it have only one upvote? $\endgroup$ Commented Oct 6, 2021 at 21:01

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