In: Anatomy and Physiology
subject: physiology
Differentiate between metabolic and respiratory acidosis and alkalosis.
The normal pH of blood is 7.35 - 7.45
When pH drops below 7.35, it is called Acidosis and when it goes above 7.45 is called Alkalosis.
Thre are two reasons for Acidosis and Alkalosis.
1. Metabolic cause (it is represented by Bicarbonate, HCO3)
2. Respiratory cause (it is represented by the partial pressure of carbon dioxide, pCO2)
Bicarbonate is an Alkaline substance, so it acts as a base for the body, which means an increased level of HCO3 will cause metabolic alkalosis and decrease the level of HCO3 in blood will cause Metabolic Acidosis.
Carbon dioxide is an acidic substance, so it acts as an acid for the body, which means an increased level of pCO2 will cause Respiratory acidosis and a decreased level of pCO2 will cause respiratory alkalosis.
The normal value of pCO2 - 35 to 45 mmHg
The normal value of HCO3 - 22 to 28 mEq/L
Example -
1. pH - 7.5, pCO2 - 40 mmHg, HCO3 - 32 mEqL (it is Metabolic Alkalosis because here HCO3 is in the high range, HCO3 represents the Metabolic part).
2. pH - 7.30, pCO2 - 40 mmHg, HCO3 - 18 mEq/L (it is Metabolic Acidosis because here HCO3 is in low range, HCO3 represents Metabolic part).
3. pH - 7.30, pCO2 - 55 mmHg, HCO3 - 24 mEq/L - (It is Respiratory Acidosis because here pCO2 is in high range. pCO2 represents Respiratory part).
4. pH - 7.5, pCO2 - 25 mmHg, HCO3 - 24 mEq/L - (It is Respiratory Alkalosis because here pCO2 is in low range. pCO2 represents Respiratory part).