Buffers and How They Work
Buffers in the body help to maintain homeostasis in the blood. During exercise, the muscles use up oxygen as they convert chemical energy in glucose to mechanical energy. This oxygen comes from hemoglobin in the blood. CO2 and H+ are produced during the breakdown of glucose and are removed from the muscle through the blood. This causes chemical changes in the blood. These chemical changes cause the pH level of the blood to drop. If the pH in the body drops below 7.4, a condition known as acidosis occurs. This can be very serious, because many of the chemical reactions that occur in the body, are pH-dependent. If the pH drops below 6.8 or rises above 7.8, there is a chance of death. Fortunately, we have buffers in the blood to protect against large changes in pH.

Buffers are dissolved in the blood, various organs help them in keeping the body at homeostasis. For example, the kidneys help remove excess chemicals from the blood. The kidneys remove H+ ions and other components of the pH buffers that build up. Acidosis that results from failure of the kidneys to perform this excretory function is known as metabolic acidosis.

Another example of an organ assisting buffers in maintaining homeostasis is the lungs. The lungs provide a faster way to help control the pH of the blood. The increased-breathing during exercise helps to work against the pH-lowering effects of exercise by removing CO2, a component of the main pH buffer in the blood. Acidosis that results from failure of the lungs to eliminate CO2 as fast as it is produced is known as respiratory acidosis.

Buffers in solutions resist to changes in the pH of a solution when hydrogen ions or hydroxide ions are added or removed. An acid-base buffer contains a weak acid and its conjugate base or salt. Buffers work because the concentrations of the weak acid and its salt are large compared to the amount of protons or hydroxide ions added or removed. When protons are added to the solution from an external source, some of the base part of the buffer is converted to the weak-acid component so therefore most of the protons added are used up.