1.What are the structural characteristics of the heart The heart is divided into the left heart and the right heart on both sides, and the left and right hearts are each divided into the left atrium, left ventricle and right atrium, right ventricle, a total of four heart chambers. The role of the heart is similar to that of a water pump, which pumps blood from the veins into the right side of the heart (from the right atrium into the right ventricle) around the clock, and then pumps blood into the lungs, where the blood receives oxygen and flows into the left side of the heart, and then shoots into the arterial vessels through the left atrium to the left ventricle, and transports blood to all parts of the body through the aorta and its systemic arterial branches, providing oxygen and nutrients to all living cells of the body. 2.What are the valves in the heart? The valve between the right atrium and the right ventricle is composed of three valves, called the “tricuspid valve”. The valve between the left atrium and the left ventricle is composed of two valves, so people call it the “mitral valve. Between the right ventricle and the pulmonary artery, there is a valve consisting of three semilunar valves, which is called the “pulmonary valve”. When the blood absorbs enough oxygen and expels carbon dioxide in the lungs, it flows into the left atrium, goes to the left ventricle, and then is discharged from the other exit of the left ventricle (aortic valve), and the valve between the aorta and the left ventricle is called the “aortic valve”. 3.What is the wall of the heart? The wall of the heart consists of four chambers, the epicardium, the myocardium and the endocardium. The epicardium, which covers the surface of the heart, is a very thin membrane (plasma membrane). The endocardium is a continuation of the endovascular membrane and is lined with the inner surface of the myocardium. The folds at the atrial orifice form the mitral and tricuspid valves, and the folds at the aortic and pulmonary orifices form the aortic and pulmonary valves. We often refer to endocarditis as the inflammation that occurs mainly at the valves, such as rheumatic endocarditis and subacute bacterial endocarditis. In between the thin epicardium and endocardium is the thick myocardium, and what we usually call myocarditis refers to inflammatory lesions within the myocardium. This shows that the myocardium is only an important part of the heart wall. 4, what is the conduction tissue of the heart We will start from the sinoatrial node, through the three inter-nodal bundles to the atrioventricular junction, and then to the left and right bundle branches and Purkinje fibers of this set of conduction pathways called the conduction tissue of the heart. The sinus node is a small node under the epicardium at the junction of the right atrium and the superior vena cava, which can give orders to the heart to contract on time; it also goes to another “node” located in the lower part of the atrial septum, which is called the atrioventricular node, and passes through the atrioventricular junction to the left and right conduction bundles, and the left and right bundle branches descend along the deep endocardial surface on both sides of the ventricular septum respectively. The left and right bundle branches descend along the deep endocardial surface of both sides of the ventricular septum, and continue to branch out, getting finer and finer, finally dividing into tiny “Purkinje fibers” distributed in the myocardium of the left and right ventricles. 5.What is the pericardium The blind sac that surrounds the heart and the roots of the great vessels is called the pericardium. The pericardium is divided into two layers: the epicardium (plasma membrane) immediately adjacent to the heart is called the dirty layer, and the wall layer is composed of the plasma membrane and the outer fibrous layer. The two layers are closely attached to the root of the great vessels and form a cavity called the pericardial cavity. It contains a small amount of fluid and plays the role of lubrication in the mechanical device. 6.What is called coronary circulation Coronary circulation, that is, the blood circulation constituted by the arteries and veins that nourish the heart itself. The coronary circulation is the shortest circulation in the body circulation. The blood in the coronary vein mainly flows back into the right atrium through the coronary sinus, and the coronary artery starts at the root of the aorta, which has higher pressure and faster flow rate, and the anastomotic branches between the coronary arteries are relatively few and thin. 7, what is the normal human heart rate In a quiet state, the average heart rate of healthy adults is about 72 times / minute, the normal adult heart rate fluctuations range from 60-100 / minute, women’s heart rate is faster than men’s heart rate, physical activity and mental excitement can increase the heart rate. Women’s heart rate is faster than men’s heart rate, but everything is relative, for example, people who often engage in heavy physical labor or physical exercise have a slower heart rate, which can be less than 60 beats per minute, but this can never be said to be a pathological state, and should be considered comprehensively.