💓 HEART 📘 Essential for Anatomy & Physiology, Medical-Surgical Nursing & Staff Nurse Competitive Exams ✅ I. Introduction / Definition: The heart is a muscular organ roughly the size of a clenched fist, located in the mediastinum (center of thoracic cavity), slightly tilted to the left.✅ It functions as a double pump to circulate oxygenated and deoxygenated blood throughout the body. 📖 II. External Features of the Heart: 🔹 Cone-shaped