What is the structure of heart like?

The heart is a muscular organ with four chambers: two atria (singular: atrium) and two ventricles. The atria are the upper chambers of the heart and the ventricles are the lower chambers. The heart is divided into a right side and a left side. The right side of the heart pumps deoxygenated blood to the lungs, while the left side of the heart pumps oxygenated blood to the rest of the body.

The heart wall is made up of three layers: the epicardium, the myocardium, and the endocardium. The epicardium is the outermost layer and it is made up of connective tissue. The myocardium is the middle layer and it is made up of cardiac muscle cells. The endocardium is the innermost layer and it is made up of endothelial cells.

The heart valves are located between the atria and the ventricles and they prevent backflow of blood. The mitral valve (also known as the left atrioventricular valve) is located between the left atrium and the left ventricle. The tricuspid valve (also known as the right atrioventricular valve) is located between the right atrium and the right ventricle. The aortic valve is located between the left ventricle and the aorta, and the pulmonary valve is located between the right ventricle and the pulmonary artery.

The coronary arteries supply oxygen-rich blood to the heart muscle. The coronary veins drain deoxygenated blood from the heart muscle.