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Why is double circulation of blood necessary in human beings?

Class 12th Biology

Asked By Panchi Jaiswal


  • Double circulation is the flow of blood through the heart twice. Initial
    flow is finished when deoxygenated blood is brought to heart and then
    pumped to lung for oxygenation. The second flow is from lungs to heart
    and then back to the body. The transmission is important as it helps in
    oxygenation of blood.
  • Double circulation describes the fact that our oxygenated and
    deoxygenated blood is kept separate in our hearts. In fish
    (two-chambered heart) and amphibians (three-chambered heart), the
    oxygenated and deoxygenated blood is allowed to mix in the ventricles,
    in mammals and birds (four-chambered heart), the oxygenated and
    deoxygenated blood is kept separate. Fish and amphibians are
    cold-blooded, meaning that they conform to the temperature of their
    environment. Mammals and birds are warm blooded. They maintain a
    constant internal temperature, despite the environment. Maintaining a
    constant internal temperature allows mammals and birds to carry-out body
    processes more efficiently, but it requires more energy. Without
    double circulation, the body tissues would not receive enough oxygen to
    maintain a constant temperature, and would die.
  • Double circulation enables the circulatory and respiratory systems in
    the human body more efficiently deliver oxygen to the body by separating
    oxygen-rich blood ready to deliver oxygen to the body from oxygen-poor
    blood that needs to travel through the lungs to absorb ore oxygen before
    it can be sent back through the body.
    First, oxygen-poor blood is pumped from the heart to the lungs, where it
    absorbs oxygen and returns to the heart. The heart then pumps the
    oxygen-rich blood to the body, where it delivers oxygen to the cells
    that need it. The blood returns to the heart after delivering most of
    its oxygen, where it is sent back to the lungs to take up more oxygen.
    The cycle repeats with every beat of your heart.
  • The heart of human beings consist of two sides right and left.
    The right side of the heart receives de-oxygenated blood and sends it further for purification to lungs.
    The left side of the heart receives oxygenated blood which is pumped
    further and sent to all the parts of the body through blood vessels.
    This is called double circulation. The energy demands for human beings
    is too large and hence it is necessary for the separation of oxygenated
    and deoxygenated blood to meet this energy demand.

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