The heart is a muscular organ about the size of a closed fist that functions as the body’s circulatory pump. The inferior tip of the heart, known as the apex, rests just superior to the diaphragm. The base heart shaped pasta the heart is located along the body’s midline with the apex pointing toward the left side. Anatomy of the Heart Pericardium The heart sits within a fluid-filled cavity called the pericardial cavity.

The walls and lining of the pericardial cavity are a special membrane known as the pericardium. Pericardium is a type of serous membrane that produces serous fluid to lubricate the heart and prevent friction between the ever beating heart and its surrounding organs. Structure of the Heart Wall The heart wall is made of 3 layers: epicardium, myocardium and endocardium. The epicardium is the outermost layer of the heart wall and is just another name for the visceral layer of the pericardium.

Thus, the epicardium is a thin layer of serous membrane that helps to lubricate and protect the outside of the heart. Below the epicardium is the second, thicker layer of the heart wall: the myocardium. The myocardium is the muscular middle layer of the heart wall that contains the cardiac muscle tissue. Myocardium makes up the majority of the thickness and mass of the heart wall and is the part of the heart responsible for pumping blood.