Since the my first encounter with doraemon manga, I've been wondering many things, one of them is the small light.

Assuming we had an instrument, such as small light, which enabled people to grow and shrink as they wanted to, what would be the smallest and the most compact functional form of a person?

First, I can rule out that we couldn't be as small as an atom because we couldn't be function as human being if we were compressed into 1 atom. So did 1 molecule. and so did 1 cell.

Second, you need more than 1 cell to construct organs, i.e. I couldn't imagine an eye which consists only several atoms or molecules.

Therefore, there should be a limit to the the size of human organs in order to fully retain their functions and thence, there should also be a limit to the minimum size of human organs.

What are the limits of size of each of human organs?

What are the limits of size of human then?


1 Answer 1


This question is for Doctor Frankenstein!

The answer would depend on what you would accept to consider being a human.

  • Does it still need to be able to make simple calculation in order to be a human? Yes, because otherwise we would have lost some functions. But then you may ask…
  • Does it need to have big enough hands in order to fulfill the social function of hand shaking.
  • Does it has to be attractive to the other sex?
  • Does it need a heart or is it fine if oxygen diffusion through tissue only is enough for this creature to live?

I guess that if you change the number of cells you will necessarily change the functionality. I am not saying that small guys are not as functional as big guys. For example, big guys are better runner, while small guys are better climber.

  • Are we allowed to shrink the cells to have minimal sized cells?
  • Are we allowed to shorten the DNA in order to shrink the cells?


  • There are approximatively 200 different cell types in a human
    • My reference is not a peer-reviewed article (ref). Wikipedia lists cell types and it doesn't seem to go over 200. However, it is important to realize that it probably very much depend on how you define cell types.
  • Terminologica Anatomica lists over 7,500 names parts of the human body
  • There are 13 or 14 (depending on the gender) gland types
  • This article provides an estimation of the number of cells in the human body
  • Here (wikipedia) is a discussion on the concept of the minimal cell
  • Here and here (biology.SE) are discussions on the minimum number of genes/amino acid to sustain life
  • Here (biology.SE) is a discussion on which species has been found to have the smallest genome
  • $\begingroup$ Great answer. But only 200 cell types? I think that's a vast underestimation... $\endgroup$
    – Memming
    May 31, 2015 at 19:19
  • $\begingroup$ Thanks. I added a comment in my answer to explain why I picked 200 and clarify that this number might be subject to semantic issues. $\endgroup$
    – Remi.b
    May 31, 2015 at 21:02

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