Question

Of the three buffering mechanisms in the body, which is the strongest?

a) Bicarbonate buffer system
b) Phosphate buffer system
c) Protein buffer system
d) Ammonia buffer system

Answer 1

Option (a), The strongest buffering mechanism in the body is the bicarbonate buffer system, which efficiently manages pH changes, especially those that make the blood more acidic.

Step-by-step explanation:

Of the three buffering mechanisms in the body, the bicarbonate buffer system is considered the strongest. Buffers work by absorbing excess hydrogen and hydroxide ions to prevent increases or decreases in pH. The bicarbonate system, in particular, includes bicarbonate ions (HCO3-) and carbonic acid (H2CO3) and is present in blood plasma. Bicarbonate ions and carbonic acid exist in a 20:1 ratio when the blood pH is within the normal range, making it an efficient system for handling the metabolic waste which is primarily acidic.

The bicarbonate buffer is pivotal for managing pH in the interstitial fluid (IF) surrounding the cells throughout the body. Furthermore, the respiratory system regulates carbonic acid levels by expelling CO2, and the renal system controls blood bicarbonate levels by conserving bicarbonate ions in the renal filtrate. Besides the bicarbonate buffer system, the body also utilizes other systems like the protein buffer system, which includes plasma proteins and hemoglobin, and the phosphate buffer system, but the bicarbonate buffer system is the primary one due to its role in blood plasma and its ability to interact with respiratory and renal mechanisms.