The thoracic cavity lodges heart with pericardium with mediastinum present in between the two lungs. Blood vascular system consists of heart and blood vessels. Mediastinum is divided into superior, anterior, middle and posterior mediastinum. Pericardium consists of outer fibrous and inner serous (parietal and visceral) layers with oblique and transverse sinuses. Heart consists of 4 chambers—left and right atria, left and right ventricles, apex and base. External and internal features of all chambers are discussed. Nerve supply of heart is by superficial and deep cardiac plexus. Heart is supplied by coronary arteries and drained by coronary sinus, anterior cardiac veins and venae cordis minimae. Lymph drains into superior mediastinal and right tracheobronchial nodes. Different branches of aorta and important veins with tributaries are discussed. Histological features of elastic/large artery, muscular/medium-sized artery and large vein are illustrated.