🛌🧠 Normal Sleep Physiology 📘 Essential for Mental Health Nursing, Physiology, and Staff Nurse Competitive Exams 🔰 Definition of Sleep: Sleep is a reversible state of altered consciousness where the body and mind rest. It is essential for physical restoration, brain function, emotional regulation, and memory consolidation. ✅ It is actively regulated by the brain and follows a circadian rhythm (24-hour cycle). “Sleep is not a passive state, but an