![Structure of heart download](https://cdn3.cdnme.se/5447227/9-3/1_64e61dfaddf2b33c615a3cd3.png)
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The myocardium is the muscular middle layer of the heart wall that contains the cardiac muscle tissue. Below the epicardium is the second, thicker layer of the heart wall: the myocardium. Thus, the epicardium is a thin layer of serous membrane that helps to lubricate and protect the outside of the heart. The epicardium is the outermost layer of the heart wall and is just another name for the visceral layer of the pericardium. The heart wall is made of 3 layers: epicardium, myocardium and endocardium. The pericardium has 2 layers-a visceral layer that covers the outside of the heart and a parietal layer that forms a sac around the outside of the pericardial cavity. Besides lubrication, the pericardium serves to hold the heart in position and maintain a hollow space for the heart to expand into when it is full. 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.
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The walls and lining of the pericardial cavity are a special membrane known as the pericardium.
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The heart sits within a fluid-filled cavity called the pericardial cavity. Because the heart points to the left, about 2/3 of the heart’s mass is found on the left side of the body and the other 1/3 is on the right. The base of the heart is located along the body’s midline with the apex pointing toward the left side. The inferior tip of the heart, known as the apex, rests just superior to the diaphragm. Pulmonary arteries and veins, and the vena cava. On its superior end, the base of the heart is attached to the aorta, The heart is located in the thoracic cavity medial to the lungs and posterior to the sternum. It takes in deoxygenated blood through the veins and delivers it to the lungs for oxygenation before pumping it into the various arteries (which provide oxygen and nutrients to body tissues by transporting the blood throughout the body). The heart is a muscular organ about the size of a closed fist that functions as the body’s circulatory pump.
![Structure of heart download](https://cdn3.cdnme.se/5447227/9-3/1_64e61dfaddf2b33c615a3cd3.png)