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Acid -base balance The body's balance between acidity and alkalinity is referred to as acid-base balance.Blood acidity increases when the o Level of acidic compounds in the body rises (through increased intake or production, or decreased elimination) o Level of basic (alkaline) compounds in the body falls (through decreased intake or production, or increased elimination) Blood alkalinity increases when the level of acid in the body decreases or when the level of base increases.Types of acidosis and alkalosis Acidosis and alkalosis are classified depending on their primary cause as o Metabolic o Respiratory Metabolic acidosis and metabolic alkalosis are caused by an imbalance in the production of acids or bases and their excretion by the kidneys.In clinical settings, we evaluate person's acid-base balance by measuring the pH and levels of carbon dioxide (an acid) and bicarbonate (a base) in the blood.Types of Acid-Base Disorders There are two abnormalities of acid-base balance: o Acidosis: The blood has too much acid (or too little base), resulting in a decrease in blood pH. o Alkalosis: The blood has too much base (or too little acid), resulting in an increase in blood pH. Acidosis and alkalosis are not diseases but rather are the result of a wide variety of disorders.The respiratory center regulates the amount of carbon dioxide that is 63 exhaled by controlling the rate and depth of breathing (ventilation).Respiratory acidosis and respiratory alkalosis are caused by changes in carbon dioxide exhalation due to lung or breathing disorders.Controlling pH involves the use of chemical buffer systems, which guard against sudden shifts in acidity and alkalinity.As carbon dioxide accumulates in the blood, the pH of the blood decreases (acidity increases).Compensation for acid-base disorders Each acid-base disturbance provokes automatic compensatory mechanisms that push the blood pH back toward normal.Hemoglobin and oxyhemoglobin, protein and phosphate buffer pairs.The pH buffer systems are combinations of the body's own naturally occurring weak acids and weak bases.The kidneys are able to affect blood pH by excreting excess acids or bases.2.3.

Acid -base balance
The body's balance between acidity and alkalinity is referred to as acid-base balance. The
blood's acid-base balance is precisely controlled because even a minor deviation from the
normal range can severely affect many organs.
An important part of being healthy is for the blood to maintain a normal degree of acidity or
alkalinity. The acidity or alkalinity of any solution, including blood, is indicated on the pH
scale. The pH scale, ranges from 0 (strongly acidic) to 14 (strongly basic or alkaline). A pH of
7.0, in the middle of this scale, is neutral. Blood is normally slightly basic, with a normal pH
range of about 7.35 to 7.45. Usually, the body maintains the pH of blood close to 7.40.
In clinical settings, we evaluate person's acid-base balance by measuring the pH and levels of
carbon dioxide (an acid) and bicarbonate (a base) in the blood.
Blood acidity increases when the
• Level of acidic compounds in the body rises (through increased intake or production,
or decreased elimination)
• Level of basic (alkaline) compounds in the body falls (through decreased intake or
production, or increased elimination)
Blood alkalinity increases when the level of acid in the body decreases or when the level of
base increases.
Control of Acid-Base Balance
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The body uses different mechanisms to control the blood's acid-base balance. These
mechanisms involve the
• Buffer systems
• Lungs
• Kidneys

1. Buffer systems
   Activated in seconds. It is the fastest and the first line of defense. The most important buffer
   system is the bicarbonate-carbonic acid system. Hemoglobin and oxyhemoglobin, protein and
   phosphate buffer pairs. Controlling pH involves the use of chemical buffer systems, which
   guard against sudden shifts in acidity and alkalinity. The pH buffer systems are combinations
   of the body's own naturally occurring weak acids and weak bases. These weak acids and bases
   exist in pairs that are in balance under normal pH conditions. The pH buffer systems work
   chemically to minimize changes in the pH of a solution by adjusting the proportion of acid and
   base.


2. Role of the lungs
   Activated in minutes to hours. It is second defense to activate. H+ concentration stimulate
   breathing center. The body controls blood pH by the release of carbon dioxide from the lungs.
   Carbon dioxide is constantly produced by cells. The blood carries carbon dioxide to the lungs,
   where it is exhaled. As carbon dioxide accumulates in the blood, the pH of the blood decreases
   (acidity increases). The respiratory center regulates the amount of carbon dioxide that is
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   exhaled by controlling the rate and depth of breathing (ventilation). Consequently, the pH of
   the blood, increases as breathing becomes faster and deeper and vice versa.


3. Role of the kidneys
   Activated in days. It is the strongest mechanism for control. The kidneys are able to affect
   blood pH by excreting excess acids or bases. The kidneys make these adjustments more
   slowly than the lungs do; this compensation generally takes several days.
   Types of Acid-Base Disorders
   There are two abnormalities of acid-base balance:
   • Acidosis: The blood has too much acid (or too little base), resulting in a decrease in
   blood pH.
   • Alkalosis: The blood has too much base (or too little acid), resulting in an increase in
   blood pH.
   Acidosis and alkalosis are not diseases but rather are the result of a wide variety of disorders.
   The presence of acidosis or alkalosis provides an important clue that a serious problem exists.
   Types of acidosis and alkalosis
   Acidosis and alkalosis are classified depending on their primary cause as
   • Metabolic
   • Respiratory
   Metabolic acidosis and metabolic alkalosis are caused by an imbalance in the production of
   acids or bases and their excretion by the kidneys.
   Respiratory acidosis and respiratory alkalosis are caused by changes in carbon dioxide
   exhalation due to lung or breathing disorders.
   Compensation for acid-base disorders
   Each acid-base disturbance provokes automatic compensatory mechanisms that push the blood
   pH back toward normal. In general, the respiratory system compensates for metabolic
   disturbances while metabolic mechanisms compensate for respiratory disturbances. At first,
   the compensatory mechanisms may restore the pH close to normal. But, if the blood pH has
   changed significantly, it means that the body's ability to compensate is failing.