The sac that surrounds and protects the heart is called?

A. Pericardial sac: The pericardial sac, also known as the pericardium, is a double-walled sac that surrounds and protects the heart. It consists of an outer fibrous layer and an inner serous layer, which produces pericardial fluid to reduce friction between the heart and surrounding structures during heartbeats. This structure provides support and helps maintain the position of the heart within the thorax. B. Endocardial sac: The endocardium is the innermost layer of the heart wall that lines the heart chambers and covers the heart valves. It does not refer to a protective sac surrounding the heart. C. Pleural sac: The pleural sac consists of two layers (visceral and parietal pleura) that encase the lungs and provide a lubricated surface for lung expansion and contraction during respiration. It is not related to the heart. D. Myocardial sac: The myocardium refers to the muscular middle layer of the heart wall responsible for contraction and pumping blood. It is not a sac and does not surround or protect the heart.