A Which of the following is a regulatory function of blood?
A) delivery of oxygen to body cells
B) maintenance of normal pH in body tissues
C) prevention of blood loss
D) transport of metabolic wastes from cells
The Correct Answer and Explanation is :
The correct answer is B) maintenance of normal pH in body tissues.
Explanation:
Blood has several vital functions in the body, and one of its important roles is to maintain homeostasis, including the regulation of pH levels in tissues. The body’s normal pH is slightly alkaline, usually around 7.35 to 7.45. The blood plays a crucial regulatory role in keeping this balance stable, despite the continuous production of acids and bases in various metabolic processes. The regulation of pH is vital because even small deviations from the normal pH range can impair enzyme activity and cellular function, potentially leading to serious health problems.
Blood regulates pH primarily through buffer systems. The bicarbonate buffer system is the most important mechanism, where bicarbonate ions (HCO3⁻) and carbonic acid (H2CO3) help neutralize excess acids or bases. When the blood becomes too acidic (low pH), the bicarbonate ions act as a base to neutralize the acids. Conversely, when the blood becomes too alkaline (high pH), carbonic acid dissociates to release hydrogen ions (H⁺), which act as acids to lower the pH.
In addition to the bicarbonate buffer system, the respiratory and renal systems also help regulate blood pH. The lungs control the levels of carbon dioxide (CO2), and the kidneys help excrete excess acids or bases to restore pH balance. Together, these mechanisms ensure that the blood maintains a stable pH, providing an optimal environment for cellular processes and enzyme functions.
While the other options listed (A, C, D) describe functions of blood, such as oxygen transport, clotting, and waste removal, they are not primarily regulatory functions. Blood’s role in regulating pH is critical for maintaining the biochemical equilibrium needed for normal body functions.