Heart

• The fibrous pericardium and serous pericardium are innervated by the phrenic nerve, which is derived primarily from cervical nerve 4 but also has contributions from the 3 and 5.
• Parasympathetic innervation of the heart = vagus nerve
• Endocardium (simple squamous, mesodermal origin). Myocardium. Epicardium (visceral layer of serous pericardium, envelops coronary arteries). Pericardial cavity (contains pericardial fluid). Parietal layer of serous epicardium. Fibrous epicardium.
• Septomarginal trabecula/Moderator band = Important in the electrical conducting system of the heart as part of the right bundle branch travels through the band
• Semilunar valves are in both the aorta and pulmonary trunk, and prevent backflow of blood into ventricles during diastole