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sliding filament theory and bone

Discussion in 'DAT Discussions' started by elaine07, May 3, 2007.

  1. elaine07


    Apr 2, 2007
    anyone know if this two answers are right or not?

    1) Bones grow in diameter by the combined action of which two of the three bone cell types?

    a) Osteoblasts and osteocytes
    b) Osteoblasts and osteoclasts
    c) Osteoclasts and osteocytes
    d) osteocytes and osteons

    I am confused between b and d.

    2) According to the sliding filament theory:
    a) actin moves past myosin
    b) myosin moves past actin
    c) tropomyosin moves past actin
    d) troponin moves past myosin

    I thought the answer is A...but someone keep on arguing with me saying it's B.
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  3. Ex_EE

    Ex_EE 2+ Year Member

    Sep 23, 2006
    For number 1 the answer is b. From wikipedia:
    "An osteoblast (from the Greek words for "bone" and "germ" or embryonic) is a mononucleate cell that is responsible for bone formation. Osteoblasts produce osteoid, which is composed mainly of Type I collagen. Osteoblasts also are also responsible for mineralization of the osteoid matrix. Bone is a dynamic tissue that is constantly being reshaped by osteoblasts, which build bone, and osteoclasts, which resorb bone."

    For number 2. A is right. Check out this site.
  4. DentalKitty

    DentalKitty 5+ Year Member

    Mar 12, 2007
    Yep, 1 is B:

    "Even though bones stop growing in length in early adulthood, they can continue to increase in thickness or diameter throughout life in response to stress from increased muscle activity or to weight. The increase in diameter is called appositional growth. Osteoblasts in the periosteum form compact bone around the external bone surface. At the same time, osteoclasts in the endosteum break down bone on the internal bone surface, around the medullary cavity. These two processes together increase the diameter of the bone and, at the same time, keep the bone from becoming excessively heavy and bulky."

    I also agree with 2 being A. The info is easily searched for online or in a textbook.
  5. RozhonDDS

    RozhonDDS 7+ Year Member

    Jan 2, 2006
    1) B
    2) A

    Those are def the right answers

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