Acid and Base Balance

There are two types of buffer systems within the body: Chemical buffers and physiological buffers

Chemical buffers: “substances that bind hydrogen ion and remove it as the concentration of a solution begins to rise, and releases hydrogen ions as the concentration begins to fall”

• Three major chemical buffer systems: bicarbonate, phosphate, and protein

  • Bicarbonate buffer system

    • A solution of both carbonic acid and bicarbonate ions. When the body’s pH balance is acidic(pH under 7.35), the lungs and kidneys will remove carbon dioxide in order to help balance or neutralize hydrogen ions. If the body is in an alkalotic or basic state (pH over 7.45) , the kidneys will then excrete bicarbonate iron and elevate the hydrogen ion concentration to create a more acidic environment

  • Phosphate buffer system

    • Works very similarly to the bicarbonate buffer system; however, it has a much stronger effect

  • Protein buffer system:

    • Is responsible for about 75% of all chemical buffering ability of the fluids of the body. Is due to the certain side groups of amino acids on proteins. Some of these amino acids allow the protein buffer system to release hydrogen ions, such as when the pH is becoming alkaline to create a more acidic environment. Others will bind hydrogen ions because the environment has become acidic: raises pH to normal levels

Physiological buffers: systems in the body that control the body’s output of acids, bases, and carbon dioxide

• Urinary and respiratory systems

  • Urinary system equalizes the greatest amount of acid, but is very slow (takes several hours to days in order to respond to changes in acidity). The respiratory system is much faster, but is not able to buffer as much (responds within a few minutes)

A person can only survive a short amount of time (a few hours) if their pH falls below 7 or above 7.7, and can be quickly fatal if it falls below 6.8 and above 8.0. When the body is in a state of acidosis, the central nervous system becomes depressed (confusion, disorientation, and coma). In alkalosis, skeletal muscles become over stimulated ( muscle spasms, convulsions, or respiratory paralysis)

Body buffer systems are designed to compensate for acid and basic imbalances