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Pascal Law and Human Body

  1. Aug 18, 2014 #1
    According to Pascal Law, when there is an increase in pressure at any point in a confined fluid, there is an equal increase at every other point in the container. Then why doesn't our entire body experiences the same pressure throughout the body when we press our finger. Isn't the entire body filled with fluid, i.e. blood and water?
  2. jcsd
  3. Aug 18, 2014 #2


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    Our bodies don't behave as perfect fluids. They're covered with skin that stretches differently in different directions, the lungs are full of air which obeys Boyle's law instead of Pascal's, the heart and arteries are working hard at creating pressure differentials throughout the circulatory system, membranes in the kidneys and digestive track do interesting things with osmotic pressures, bones, tendons, and connective tissues are fairly solid....

    Modeling the human body as a bag filled with liquid isn't very accurate across a wide range of conditions, including (not coincidentally) those which we most often encounter in daily life.
  4. Aug 19, 2014 #3
    But sir, still our body has a large portion of fluid ranging from blood to hormones. So what the problems?
  5. Aug 19, 2014 #4


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    The problem is, the human body is still not a bag of skin with a bunch of fluid inside. When you move your body, you don't slosh inside, like when you carry a pail half-filled with water. Your bones, organs, muscles, etc. behave closer to solid materials than they do liquids.
  6. Aug 19, 2014 #5


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    You could model the body as a sausage shaped balloon, full of water (it would need to be contained in some sort of basket or it would form a tear drop shape ). In that model, if you squeezed the top, the pressure at the bottom would also increase.

    It is usually very problematical to try to apply simple basic ideas in Physics to complicated biological structures. There are too many variables involved for an accurate answer to be obtained.
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