The consumption of oxygen by the kidney

Discussion in 'USMLE STEP 1' started by Guest, Dec 7, 2010.

  1. Guest

    Guest Guest

    The consumption of oxygen by the kidney.

    1. Decreases as blood flow increases
    2. Is regulated by erythropoietin
    3. Remains constant as blood flow increases
    4. Directly reflects the level of sodium transport
    5. Is greatest in the medulla
  2. Guest

    Guest Guest

    The Answer is: Directly reflects the level of sodium transport

    Explanation:
    In the kidney, oxygen is used primarily to support active transport of solutes, especially sodium, out of the tubules. In fact, oxygen consumption by the kidney is directly proportional to the amount of sodium reabsorbed and is greatest in the cortex, where most tubular reabsorption of sodium occurs. An increase in renal blood flow will raise the glomerular filtration rate and increase the quantity of solute to be transported, so that oxygen consumption increases as blood flow increases and the arteriovenous oxygen difference remains constant. This is in contrast to the situation in other organs where increases in blood flow are accompanied by a decrease in arteriovenous oxygen difference. Erythropoietin is released in response to renal hypoxia and acts to increase erythrocyte production.

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