Cardiac Anatomy and Blood Flow: Right Heart Chambers

Superior Vena Cava: This large vein is responsible for collecting deoxygenated blood from the upper regions of the body. Specifically, it receives blood from the head, neck, upper limbs (arms), and the chest area. It then empties directly into the right atrium of the heart.
Inferior Vena Cava: This is another major vein, larger than the superior vena cava, which collects deoxygenated blood from the lower parts of the body. It receives blood from the trunk (torso), viscera (internal organs within the chest and abdominal cavities), and the lower limbs (legs). Like the superior vena cava, the inferior vena cava also terminates in the right atrium.
Right Atrium: Both the superior and inferior vena cava converge and deliver their deoxygenated blood to the right atrium, one of the four chambers of the heart. This chamber acts as a collecting pool for blood returning from the systemic circulation before it's pumped to the lungs.

Four Chambers: The human heart consists of four distinct chambers: the right atrium, right ventricle, left atrium, and left ventricle.
Four Valves: In addition to its four chambers, the heart also contains four valves. The primary function of these valves is crucial for maintaining efficient blood flow throughout the circulatory system. Their purpose is to ensure that blood moves in a unidirectional manner, preventing any backflow that would compromise cardiac efficiency.

Right Atrium to Right Ventricle: Blood, having accumulated in the right atrium, exits this chamber by passing through the tricuspid valve. This particular valve is named the tricuspid valve because it is composed of three distinct flaps, or cusps. Upon passing through this valve, the blood enters the right ventricle.
Right Ventricle to Pulmonary Artery: After filling the right ventricle, the deoxygenated blood is then ejected from this chamber. It passes through the pulmonary valve and subsequently enters the pulmonary artery.
- Pulmonary Artery - A Unique Case: It's important to note that despite being called an "artery" (which typically carries oxygenated blood away from the heart), the pulmonary artery carries deoxygenated blood. This is because, by definition, an artery is any vessel that carries blood away from the heart, regardless of its oxygen content. In this specific circuit, the blood in the pulmonary artery is depicted as "blue" (lacking oxygen) because it is on its way to the lungs to become oxygenated.

When viewing diagrams or discussing the heart, it's crucial to distinguish between left and right from the patient's perspective. Therefore, what appears on the right side of an illustration or observer's view actually corresponds to the patient's left, and vice versa. For example, the "left one" refers to the patient's left side of the heart, and the "right one" refers to the patient's right side.