People with heart-related diseases often hear the terms “coronary artery,” “anterior descending branch,” “gyral branch,” “mitral valve,” and “tricuspid valve” when they visit the clinic. “However, they do not have a clear understanding of what these terms stand for. When I listen to them, I am so confused that I do not have a proper understanding of the condition. Now, we would like to give a brief introduction to the structure of the heart. The basic structure of the heart The heart is the organ that provides the main pressure for blood flow and carries blood to all parts of the body. The human heart is located in the lower left of the middle of the chest and is about the size of a fist. In women, the heart is usually smaller and lighter than in men. The heart is made up of heart muscle and four chambers: the left atrium, the left ventricle, the right atrium and the right ventricle. The left and right atria are separated from each other by a septum, and the right and left ventricles are separated from each other by valves (atrioventricular valves) that allow blood to flow only from the atria into the ventricles and not backwards. The electrophysiology of the heart The heart beats constantly and regularly throughout life. The “heartbeat” is actually the rhythmic contraction and diastole of the heart. The average adult heart beats about 60-80 times per minute, with an average of 75. In children, the heart rate is faster, and in infants under 9 months of age, the normal heart rhythm can be about 140 beats per minute. There is a conduction system of special myocardial fibers within the heart wall, whose function is to send out command signals and conduct them to all parts of the heart, causing the atrial and ventricular muscles to contract according to a certain rhythm. This system consists of the sinus node, the atrioventricular node, the atrioventricular bundle, the right and left atrioventricular bundle branches located on either side of the ventricular septum, and many fine branches distributed to the ventricular papillary muscle and ventricular wall in the order of conduction. The sinoatrial node is located under the epicardium in the right atrium near the entrance to the superior vena cava and is the normal pacing point. The pacing cells generate cardiac rhythmic commands and transmit them through the transition cells to the atrial myocardium, causing it to contract. At the same time, rhythmic commands are transmitted down the inter-nodal bundle to the AV node. The AV node transmits the commands from the sinus node to the ventricles to cause ventricular contraction. The atrioventricular bundle enters the septum and divides into left and right bundle branches, which travel down the endocardium and finally distribute to the ventricular muscle in small branches called Purkinje fibers. When the commands of the sinus node are not generated and conducted properly, it is as if the troops are out of command, and problems with the rhythm of the heart can occur. Blood supply of the heart Main vessels of the heart: Vessels of the heart (coronary vessels): (1) Left coronary artery: ①Anterior descending branches: left conical branch, oblique branch, anterior ventricular septal branch; ②Spiral branch. (2) Right coronary artery. (3) Veins of the heart: large, medium and small cardiac veins. The nutrition of the heart is supplied by the coronary arteries, which are divided into two coronary arteries, right and left, starting from the beginning of the aorta. The right coronary artery is mainly distributed in the right atrium, right ventricle and posterior part of the septum, and also in the posterior wall of the left ventricle. The left coronary artery is divided into two branches, one descending and one spiral, which are located in the left atrium, left ventricle and anterior part of the septum, and also in the anterior part of the right ventricle. When there is a problem with the blood supply to the heart, it can affect the function of the heart and even endanger life. When you understand the basic anatomy of the heart, you will be able to know the basic situation of the disease when you visit the clinic and have a preliminary understanding and judgment of your condition and the development of the disease.