The body's regulatory systems collaborate to adapt to internal and external challenges, preserving stability across varied conditions. Volume 2 focuses on endocrine regulation, cardiovascular control, renal fluid and electrolyte balance, respiratory physiology, thermoregulation, and metabolic integration. Each chapter integrates feedback loops, hormonal axes, and compensatory mechanisms with clinical examples of dysregulation. Emphasis on comparative responses to stress, exercise, and disease helps learners apply principles to patient care. Review summaries and clinical problem sets reinforce core concepts and prepare readers for applied clinical scenarios.