52. HEART

The fetal heart is the organ responsible for pumping blood through the developing body of a fetus. The gross anatomy of the fetal heart includes the following features:

1. Size: The size of the fetal heart is proportional to the size of the fetus. At full term, the heart is about the size of a small walnut.
2. Location: The fetal heart is located in the chest, slightly to the left of the midline. It is situated behind the sternum and between the lungs.
3. Chambers: The fetal heart has four chambers, including two atria and two ventricles. The right atrium receives oxygen-poor blood from the body and pumps it to the right ventricle. The right ventricle pumps the blood to the lungs for oxygenation. The left atrium receives oxygen-rich blood from the lungs and pumps it to the left ventricle. The left ventricle pumps the blood to the rest of the body.
4. Blood vessels: The fetal heart is connected to the placenta by two umbilical arteries and one umbilical vein. The umbilical arteries carry oxygen-poor blood from the fetus to the placenta, while the umbilical vein carries oxygen-rich blood from the placenta to the fetus.
5. Valves: The fetal heart has four valves that regulate blood flow between the chambers and blood vessels. These include the tricuspid valve, pulmonary valve, mitral valve, and aortic valve.
6. Conduction system: The fetal heart has a specialized conduction system that controls the heartbeat. This includes the sinoatrial (SA) node, atrioventricular (AV) node, and bundle of His.
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