ACID-BASE BALANCE AND ACID-BASE STATUS:

Acids and bases are the product of metabolism. They are transported and handled in the lungs and kidney. They are responsible for maintaining the arterial pH of 7.35-7.45 and venous pH of 7.32-7.38 which is accomplished by buffering capacity of blood and respiratory and renal regulatory mechanism.

Our body is the net producer of acids. E.g.

Biochemistry : Short Introduction

Biochemistry is the science, which deals with the chemical constituents of living cells, and with the reaction and processes, they undergo. Biochemistry, also sometimes called biological chemistry, is the study of chemical processes in living organisms, including, but not limited to, living matter. The laws of biochemistry govern all living organisms and living processes. By controlling information flow through biochemical signaling and the flow of chemical energy through metabolism, biochemical processes give rise to the complexity of life.

ACID BASE DISORDERS:

Acid base disturbances are traditionally classified as,

1.      Metabolic acidosis/alkalosis

2.      Respiratory acidosis/alkalosis.

Last 2 digit of pH = pCO₂ (e.g., if pCO₂ = 28, pH = 7.28)

cHCO₃^- + 15 = last 2 digit of pH (cHCO₃^- = 15, pH = 7.30)

RENAL MECHANISM IN THE REGULATION OF ACID BASE BALANCE:

Since the pH of urine varies from 4.5-8.0, this indicates kidney has ability to excrete various amounts of acids and bases to maintain the normal pH of blood. This ability makes the kidney the final defense mechanism against change in body pH.

Various acids produced during metabolic process are buffered in ECF at the expense of HCO₃^-. Renal excretion of acid and conservation of bicarbonate occur through various ways.

1.      The Na⁺-H⁺ exchange
2.      Production of ammonia and excretion of NH₄⁺ and
3.      Reclamation of HCO₃^-.

RESPIRATORY MECHANISM IN THE REGULATION OF ACID-BASE BALANCE:

Respiration:

Exchange of oxygen and carbon dioxide in lungs between alveolar air and blood is called external respiration, in contrast to internal respiration occurring at tissue level. Blood (RBC) will take oxygen from lungs to tissue and carbon dioxide from tissue to the lungs for exhalation.