Phosphate Buffer System

Although the phosphate buffer system is not important as an extracellular fluid buffer, it plays a major role in buffering renal tubular fluid and intracellular fluids.

The main elements of the phosphate buffer system are H2PO4- and HPO4=. When a strong acid such as HCl is added to a mixture of these two substances, the hydrogen is accepted by the base HPO4= and converted to H2PO4-.

The result of this reaction is that the strong acid, HCl, is replaced by an additional amount of a weak acid, NaH2PO4, and the decrease in pH is minimized.

When a strong base, such as NaOH, is added to the buffer system, the OH- is buffered by the H2PO4- to form additional amounts of HPO4= + H2O.

In this case, a strong base, NaOH, is traded for a weak base, NaH2PO4, causing only a slight increase in pH.

The phosphate buffer system has a pK of 6.8, which is not far from the normal pH of 7.4 in the body fluids; this allows the system to operate near its maximum buffering power. However, its concentration in the extracellular fluid is low, only about 8 per cent of the concentration of the bicarbonate buffer. Therefore, the total buffering power of the phosphate system in the extracellular fluid is much less than that of the bicarbonate buffering system.

In contrast to its rather insignificant role as an extracellular buffer, the phosphate buffer is especially important in the tubular fluids of the kidneys, for two reasons: (1) phosphate usually becomes greatly concentrated in the tubules, thereby increasing the buffering power of the phosphate system, and (2) the tubular fluid usually has a considerably lower pH than the extracellular fluid does, bringing the operating range of the buffer closer to the pK (6.8) of the system.

The phosphate buffer system is also important in buffering intracellular fluid because the concentration of phosphate in this fluid is many times that in the extracellular fluid. Also, the pH of intracellular fluid is lower than that of extracellular fluid and therefore is usually closer to the pK of the phosphate buffer system compared with the extracellular fluid.

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Responses

  • markus
    Why phosphate buffer is intracellular and not extracellular?
    3 years ago
  • mareta
    Where phosphate buffer system found?
    3 years ago
  • jessica
    What is the importance of phosphate buffer system?
    3 years ago
  • reilly
    What are phosphate baffering systems?
    3 years ago
  • yemane
    Where in the body is phosphate buffer found?
    3 years ago
  • largo
    Where can i find phosphate buffer in the body?
    3 years ago
  • tranquillina
    How phosphate buffer system works in human body?
    3 years ago
  • keri
    What is phosphate buffering system?
    3 years ago
  • Samuli
    How does the phosphate in buffer system work?
    3 years ago
  • jamila
    What is the role of the the phosphate buffer system?
    2 years ago
  • armida conti
    What the mechanism of action of phosphate buffer system?
    2 years ago
  • Anssi
    Why the bicarbonate buffer system reaction is important in the human body?
    2 years ago
  • Lana
    How do phosphate act as buffers reaction?
    1 year ago
  • lealdo
    Where is the phosphate buffer system located?
    1 year ago
  • manuel
    Where is it found Where is it traded Phosphtae?
    1 year ago
  • Daniela
    How does the phosphate buffering system work in the body?
    1 year ago
  • eglantine
    Why phosphate is phsiological buffer?
    1 year ago
  • keijo
    Where does the phospate come from in the phosphate buffering system?
    1 year ago
  • Harold
    Where does the phosphate buffering system operate specific fluid department?
    1 year ago
  • Senja Hentinen
    Why is phosphate buffer important in our body?
    1 year ago
  • Savannah Hay
    How does phophate work in the body?
    1 year ago
  • bailey
    What does phosphate effect in the buffer system?
    10 months ago
  • rosa
    How buffering action of phosphate buffer system?
    8 months ago
  • Maik Ehrlichmann
    How does the phosphate buffer system work in human body?
    6 months ago
  • Ola
    What is the function of the phosphate buffer system?
    3 months ago
  • MEBRAT
    Which buffer system is important in both the extracellular and intracellular fluids?
    3 months ago
  • fernando bruno
    Which phosphate equilibrium reaction is acting as a buffer at the high ph area?
    3 months ago
  • Marc
    How does a phodphate buffer system work?
    3 months ago
  • sarah
    Where is phosphate buffering critical in the body?
    3 months ago
  • karolin
    Which locations of the body is phosphate buffer critical?
    3 months ago
  • Levi
    Where is the phosphate buffering system found?
    3 months ago
  • jasmin
    What causes alterations in bicarbonate phosphate buffer?
    3 months ago
  • GIOACCHINA NAPOLITANI
    What doesthe phosphate buffer do in the kidney?
    2 months ago
  • delma
    Where does the phosphate system take place?
    1 month ago
  • OTTO HENTUNEN
    What is the chemical equation for phosphate buffer in renal system?
    9 days ago

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