The Bicarbonate Buffer System

This is the main extracellular buffer system which (also) provides a means for the necessary removal of the CO2 produced by tissue metabolism. The bicarbonate buffer system is the main buffer in blood plasma and consists of carbonic acid as proton donor and bicarbonate as proton acceptor :

 H₂CO₃ = H⁺ + HCO₃^–

If there is a change in the ratio in favour of H₂CO₃, acidosis results.

This change can result from a decrease in [HCO₃ ⁻ ] or from an increase in [H₂CO₃ ]

Most common forms of acidosis are metabolic or respiratory

Metabolic acidosis is caused by a decrease in [HCO₃ ⁻ ] and occurs, for example, in uncontrolled diabetes with ketosis or as a result of starvation.

Respiratory acidosis is brought about when there is an obstruction to respiration (emphysema, asthma or pneumonia) or depression of respiration (toxic doses of morphine or other respiratory depressants)

Alkalosis results when [HCO₃ ⁻ ] becomes favoured in the bicarbonate/carbonic acid ratio

Metabolic alkalosis occurs when the HCO₃ ⁻  fraction increases with little or no concomitant change in H₂CO₃

Severe vomiting (loss of H+ as HCl) or ingestion of excessive amounts of sodium bicarbonate (bicarbonate of soda) can produce this condition

Respiratory alkalosis is induced by hyperventilation because an excessive removal of CO2 from the blood results in a decrease in [H₂CO₃ ]

Alkalosis can produce convulsive seizures in children and tetany, hysteria, prolonged hot baths or lack of O2 as high altitudes.

The pH of blood is maintained at 7.4 when the buffer ratio [HCO3 − ] / [ H₂CO₃] becomes 20

FLUORIDE

The safe limit of fluorine is about 1PPM in water. But excess of fluoride causes Flourosis

Flourosis is more dangerous than caries. When Fluoride content is more than 2 PPM, it will cause chronic intestinal upset, gastroenteritis, loss of weight, osteosclerosis, stratification and discoloration of teeth

Glycogen Storage Diseases are genetic enzyme deficiencies associated with excessive glycogen accumulation within cells.

• When an enzyme defect affects mainly glycogen storage in liver, a common symptom is hypoglycemia (low blood glucose), relating to impaired mobilization of glucose for release to the blood during fasting.
• When the defect is in muscle tissue, weakness and difficulty with exercise result from inability to increase glucose entry into Glycolysis during exercise.

Various type of Glycogen storage disease are

The amino acids buffer system

Amino acids contain in their molecule both an acidic (− COOH) and a basic (− NH₂) group. They can be visualized as existing in the form of a neutral zwitterion in which a hydrogen atom can pass between the carboxyl and amino groups. 

By the addition or subtraction of a hydrogen ion to or from the zwitterion, either the cation or anion form will be produced 

Thus, when OH⁻ ions are added to the solution of amino acid, they take up H⁺ from it to form water, and the anion is produced. If H⁺ ions are added, they are taken up by the zwitterion to produce the cation form. In practice, if NaOH is added, the salt H₂N - CH₂ - COONa would be formed. and the addition of HCl would result in the formation of amino acid hydrochloride.

The Hemoglobin Buffer Systems

These buffer systems are involved in buffering CO₂ inside erythrocytes. The buffering capacity of hemoglobin depends on its oxygenation and deoxygenation. Inside the erythrocytes, CO₂ combines with H₂O to form carbonic acid (H₂CO₃) under the action of carbonic anhydrase.

At the blood pH 7.4, H₂CO₃ dissociates into H⁺ and HCO₃ ⁻ and needs immediate buffering.