Why is blood plasma called a plasma?

  1. A plasma is a gas (or, I guess a liquid, at high enough pressure or.. cause of other properties..?) witch has its electrons separated from the rest of the atom, witch is now a ion. So it is a mixture of free electrons and ions.
    Is blood plasma really this? I cannot find any information on this specific question anywhere. :(
  2. jcsd
  3. Borek

    Staff: Mentor

    Nope, blood plasma has nothing to do with the ionized gas. It is just the same name.
  4. well. that is really unsatisfying.
    But thanks..
    Maybe a history of WHY it is called a plasma and misleading people like me?
  5. Borek

    Staff: Mentor

    No idea, I would be interested to read about as well.
  6. Ryan_m_b

    Staff: Mentor

    I think the problem is that we are speaking in English. Blood plasma is very different to the plasma physicists talk about. I can't find exactly what came first, quoting the physicist wiki article

    And in the blood plasma article

    So they may have came into usage at roughly the same time. It's unlikely that blood plasma would be named after the physics version (and vice versa) so it's possible that "plasma" meant something else and both fields took the term from that. I'd be interested to know the answer :smile:
  7. If I am to trust this site, it seems the biological version came first. The story looks made up but I couldn't find anything else regarding this.
  8. Ryan_m_b

    Staff: Mentor

    Interesting. It's in a letter from nature, I'd be prepared to stake that it was true (or at least as true as we are going to get).
  9. On second thought it does seem like a reputable site.
  10. The results of my Google based researches:

    1712, "form, shape" (earlier plasm, 1620), from L.L. plasma, from Gk. plasma "something molded or created," from plassein "to mold," originally "to spread thin," from PIE *plath-yein, from base *pele- "flat, to spread" (see plane (1)). Sense of "liquid part of blood" is from 1845; that of "ionized gas" is 1928.

    1. Anatomy, Physiology . the liquid part of blood or lymph, as distinguished from the suspended elements.

    Neither is it the only time physics has borrowed from biology - 'fission' is a term that followed the same path.
  11. DaveC426913

    DaveC426913 16,538
    Gold Member

    This is not any scientific issue; it is an issue of the roots of our langauge in Greek.

    Plasma is Greek for 'formative substance' - a general term, obviously picked up independently by both historical physicists and historical biologists.

  12. Andy Resnick

    Andy Resnick 6,143
    Science Advisor
    Education Advisor

    The term 'plasma' for the liquid part of blood dates from 1845; that for a gas of charged particles from 1928:



    "We shall use the name plasma to describe this region containing balanced charges of ions and electrons." (from the above)

    I couldn't find the 1845 reference.
  13. DaveC426913

    DaveC426913 16,538
    Gold Member

    Yes, but that doesn't help the OP understand the reuse of the word.
  14. If you dislike various unrelated things having the same name, you should probably take up a language other than English. :smile:
  15. bold mine

    You mean like fly (the insect), fly (like a bird), fly (as on pants), fly (as with flee), fly (as in flywheel), fly (as in the edge of a flag) and more?


    Note the first two are "biological" for what it's worth.
    Last edited: Jun 27, 2011
  16. Borek

    Staff: Mentor

    As if other languages were better. In Polish "droga" means "road", "dear" and "expensive".
  17. In English, you can do that sort of list all day long. I once read a statement that said some to the effect that while most language take in some foreign words, the English language hunts them down wholesale and kidnaps them.
  18. Andy Resnick

    Andy Resnick 6,143
    Science Advisor
    Education Advisor

    Sigh... opening paragraph of wikipedia has:

    "and dubbed "plasma" by Irving Langmuir in 1928,[4] perhaps because it characteristic that the glowing discharge mold itself to any shape into which the tube is formed.[5]".

    Note the definition of 'plasma':

    1712, "form, shape" (earlier plasm, 1620), from L.L. plasma, from Gk. plasma "something molded or created," from plassein "to mold," originally "to spread thin," from PIE *plath-yein, from base *pele- "flat, to spread" (see plane (1))

    I wonder if the OP bothered to look around...
  19. I think some folks think that research is something that other people should do for them.
  20. DaveC426913

    DaveC426913 16,538
    Gold Member

    In their defense, often looking around means asking trusted resources - such as a physics forum. I don't see why they deserve derision for asking.

    When I have car repair or computer or medical questions I could
    a] noodle around on the web and take my chances, or
    b] ask some pople I trust.
  21. Dave your point is reasonable and I may be too hard on the OP but I would personally feel lazy if I did not make some effort to find an answer to this kind of question myself before asking others. By "this kind of question" I mean one that requires no specialized knowledge to know how to phrase the question and how to understand the answer. English language is the only requirement I see for the OP's question. If I have a question for which I don't feel fully qualified to phrase the question and/or understand the answer, then I might go straight to a forum such as this to get knowledge and/or advice on where to look next.
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