- the heart is a hollow, muscular double pump. surrounding the heart is a double layer of fibrous tissue called pericardium. in between these 2 layers is a fluid filled cavity called pericardial fluid. this layer reduces friction and lubricates the surroundings.cardiac muscle tissue or myocardium makes up the major part of the heart. on the inner lining lies a smooth tissue called the endocardium. it covers the heart valves.the septum lies in between the right and left heart and completely separates them.the superior and inferior vena cava bring deoxygenated blood to the right side of the heart.plumonary artery take blood away from the right ventricle to the lungs.pulmonary veins bring oxygenated blood from the lungs to the left atrium.aorta takes blood away from the left ventricle.
