Florida State Paramedic Practice Exam

Which mechanism regulates the body's pH balance primarily through the kidneys and lungs?

1. Neurotransmission

2. Endocrine signaling

3. Homeostatic regulation

4. Alveolar ventilation

The correct answer is: Homeostatic regulation

The regulation of the body's pH balance is a critical physiological process that involves various systems, primarily the kidneys and lungs. Homeostatic regulation is the overall process through which the body maintains a stable internal environment, including maintaining an optimal pH level. The kidneys contribute to this regulation by excreting hydrogen ions and reabsorbing bicarbonate from urine. By controlling the levels of these substances, the kidneys help to regulate acid-base balance over a longer duration. This mechanism is essential because it allows the body to compensate for metabolic acid or base imbalances that might arise from dietary changes or internal metabolic processes. Simultaneously, the lungs contribute to pH balance through the process of respiration, specifically by adjusting the rate and depth of breathing. If carbon dioxide levels increase, it leads to a decrease in pH (becoming more acidic), and the body can respond by increasing respiration to expel more CO2, thus helping to restore pH balance. Conversely, if CO2 levels decrease, this can lead to alkalosis, and the body may reduce respiratory rate to retain CO2. In summary, homeostatic regulation encompasses the various mechanisms by which the kidneys and lungs work together to maintain the body’s pH within a narrow, optimal range