University:
Liberty University
Course:
BIOM 500 | Introduction to Biomedical Sciences
Academic year:

2024
Views:

431

Pages:

5
Author:

Sheha A.

Phosphate Buffer System This system is one of the mechanisms by which the body regulates acid-base balance. It is less efficient than the bicarbonate buffer system. Its components are ions only found in the plasma (H₂PO₄⁻ and HPO₄²⁻). The phosphoric acid (H₃PO₄) is a weak acid and is capable of buffering strong bases such as OH⁻ as follows: OH⁻ + H₂PO₄⁻ → H₂O + HPO₄²⁻ The concentration of phosphate is highest in ICF (intracellular fluid), hence the phosphate buffer system is an important regulator of pH in the intracellular fluid. It also buffers to a smaller degree in extracellular fluid. HPO₄²⁻ is removed when excess of H⁺ is in the kidneys. Renal fluid combines with H⁺ to form H₂PO₄⁻. The H⁺ that becomes part of H₂PO₄⁻ is effectively removed from the body. The Phosphate Buffer System The phosphate buffer system is one way the kidneys help maintain blood pH by excreting H⁺ ions in the urine. Ventilation can also affect blood pH levels of both bicarbonate and phosphate. A decrease in ventilation causes an increase in blood CO₂ which causes a decrease in blood pH. An increase in ventilation causes a decrease in blood CO₂ which causes an increase in blood pH. Regulation of Blood pH The regulation of blood pH is maintained by several mechanisms, such as: The Bicarbonate Buffer System: This is the primary buffer system in the blood. It involves bicarbonate ions (HCO₃⁻) and carbonic acid (H₂CO₃). The Phosphate Buffer System: This system uses phosphate ions (H₂PO₄⁻ and HPO₄²⁻) to buffer changes in pH. Respiratory System: The lungs can regulate blood pH by adjusting the rate and depth of breathing. Increased ventilation can decrease CO₂ levels and increase pH, while decreased ventilation can increase CO₂ levels and decrease pH. Renal System: The kidneys can excrete excess H⁺ ions or bicarbonate ions to regulate blood pH. These mechanisms work together to maintain blood pH within a narrow range, typically between 7.35 and 7.45. not stimulate the chemoreceptors and so there is a decrease in the rate of respiration (hypoventilation) so more CO2 is retained in the blood and pH is decreased and to normal Respiratory control of pH is rapid but only a short term regulator process since hyperventilation cannot reverse the loss of acid