Our blood works mostly as a carbonic acid buffer which has an optimal buffering pH of about 6.4, the pH of blood is around 7.4. What is the advantage for the body of having the buffer at the non-optimal pH??
The advantage of having the buffer in blood at a non-optimal pH is related to the mechanisms involved in maintaining the pH balance in the body. The pH of blood is normally maintained within a narrow range of around 7.35 to 7.45, which is slightly alkaline. This range is crucial for various physiological processes to function optimally.
One of the main reasons the buffer in blood is not at the optimal pH (6.4 in this case) is to allow it to effectively counteract changes in pH caused by metabolic processes or external factors. The buffer system in blood primarily consists of bicarbonate ions (HCO3-) and carbonic acid (H2CO3). When there is an increase in acidity (lower pH) in the blood due to increased production of carbon dioxide (CO2) or other acidic compounds, the bicarbonate ions act as a base and combine with the excess hydrogen ions (H+), forming carbonic acid. This reaction helps to neutralize the acidity and prevents a significant drop in blood pH.
Conversely, when there is an increase in alkalinity (higher pH) in the blood, the carbonic acid dissociates into bicarbonate ions and hydrogen ions. The released hydrogen ions help to increase the acidity and counteract the alkaline condition.
By having a buffer system that is not at the optimal pH, the body can effectively regulate blood pH within a narrower range to maintain homeostasis. This is important for various biochemical reactions, enzyme activity, and the overall functioning of cells and organs in the body. If the buffer were at the optimal pH of 6.4, it would limit its ability to act as an effective pH regulator since any deviation from that pH, in either direction, could quickly cause a more significant change in blood pH. Therefore, having a buffer at a non-optimal pH provides the body with greater stability and control over pH balance.