Heart

Superior Vena Cava

Carries deoxygenated blood from the upper body (head, arms, shoulders) to the right atrium.

Inferior Vena Cava

Carries deoxygenated blood from the lower body to the right atrium.

Right Atrium

Receives deoxygenated blood from the superior and inferior vena cava.

Tricuspid Valve (Right AV Valve)

Valve located between the right atrium and the right ventricle.

Right Ventricle

Pumps deoxygenated blood to the lungs via the pulmonary arteries.

Pulmonary Semilunar Valve

Valve through which blood exits the right ventricle into the pulmonary arteries.

Pulmonary Arteries

Carry deoxygenated blood away from the heart to the lungs (exception to typical arteries).

Pulmonary Veins

Carry oxygenated blood from the lungs back to the left atrium (exception to typical veins).

Left Atrium

Receives oxygenated blood returning from the lungs.

Bicuspid / Left AV Valve

Valve through which blood flows from the left atrium into the left ventricle.

Left Ventricle

Pumps oxygenated blood to the rest of the body; has a significantly thicker muscle wall than the right ventricle.

Aortic Semilunar Valve

Valve through which blood exits the left ventricle into the aorta.

Aorta

The main artery that transmits oxygenated blood from the left ventricle to the rest of the body.

Arteries

Blood vessels that carry blood away from the heart; typically carry oxygenated blood and have a thick smooth muscle layer.

Veins

Blood vessels that direct blood toward the heart; typically carry deoxygenated blood, have thin smooth muscle, and contain valves to prevent backflow.

Endothelium

Simple squamous epithelial tissue lining the inside of all blood vessels and the entire circulatory system.

Capillaries

Microscopic vessels where exchange occurs; situated between arterioles and venules.

Blood Flow Order Through Vessels

Heart → Aorta → Arteries → Arterioles → Capillaries → Venules → Veins → Vena Cava → Heart