CIEMT Medical and Physiology Practice Exam 2026 - Free Practice Questions and Study Guide

Blood pH is kept in a very tight window because many physiological processes depend on a precise proton concentration; enzymes and cellular functions can be disrupted if the balance shifts even a little. The pH scale is logarithmic, so small changes reflect large changes in hydrogen ion concentration. In healthy people, arterial blood sits in a narrow range just above neutrality, around 7.4. That small interval is the normal window that the body continuously maintains with buffers, respiration, and renal regulation. Among the options, the one that falls inside this normal window is the correct one, while values lower describe acidosis and values higher describe alkalosis. In short, the normal pH range is the slight alkalinity around 7.4, and anything outside that window indicates an imbalance.