The human heart is a marvel of the human body, performing life-sustaining functions through its intricate anatomy. The heart, located in the middle mediastinum between the two lungs, is a muscular organ that pumps deoxygenated blood to the lungs to pick up oxygen and release carbon dioxide. It then transports this oxygenated blood back to the body's organs. The heart is enclosed within a double-layered serous sac called the pericardium, and its shape is that of a quadrilateral pyramid. This article aims to correctly label the major internal anatomy of the heart.
External Anatomy
The heart is a conical organ shaped like a pinecone, broad at the top and tapering towards the base. The upper border of the heart, known as the base of the heart, is located at the level of the third-costal cartilage. The inferior tip of the heart, the apex, is pointed towards the anterior thoracic wall.
Interior Anatomy
Borders and Surfaces
The heart has eight borders: two superior (atria), two inferior (ventricles), two left (left arm), and two right (right arm). It also has four surfaces: the sternocostal surface (forming the right ventricle), the diaphragmatic surface (dominating the right ventricle, with a portion of the left ventricle), the pulmonary surface (impressed by the heart), and the left and right pulmonar surfaces (at the entrance end of the pulmonary trunk).
Chambers and Valves
The heart contains four heart chambers: the two atria (right and left) and two ventricles (right and left). The right atrium and ventricle receive deoxygenated blood from the systemic veins and pump it into the pulmonary circuit, while the left atrium and ventricle receive oxygenated blood from the lungs, then pump it to the systemic veins.
Key facts about the heart:
- The right atrium has one orifice, the right atrioventricular valve (tricuspid valve), between the superior and inferior vena cavae.
- The left atrium has one mitral valve (bicuspid valve) between the left atrium and left ventricle.
- A thick muscular ring that contains the opening of the aorta is called the aortic valve, located at the base of the aorta.
Blood Supply
The coronary circulation system arises from the aortic sinuses at the beginning of the ascending aorta, forming the left and right coronary arteries. These arteries travel radially around the heart, supplying oxygenated blood to every part of the heart.
Clinical Notes and References
This section discusses some common heart conditions and the symptoms they may present.
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