pulmonary
The superior vena cava.
The inferior vena cava
The inferior vena cava (or IVC), also known as the posterior vena cava, is the large vein that carries de-oxygenated blood from the lower half of the body into the right atrium of the heart.It is posterior to the abdominal cavity and runs alongside of the vertebral column on its right side (i.e. it is a retroperitoneal structure). It enters the right atrium at the lower right, back side of the heart.
Oxygen-poor blood enters the heart through the right atrium
Atrium
The right atrium is where deoxygenated blood enters the heart.
Oxygenated blood from the lungs enters the left atrium. The blood then moves from there to the left ventricle, aorta, and on the rest of the body.
left ventricle Blood enters the left & right atria. Blood entering the left ventricle came from the left atrium. Blood from the body enters the right atrium. From there it is pumped to the right ventricle, through the lungs, to the left atrium, to the left ventricle, then throughout the body. Then back to the right atrium...
When blood leaves the lungs through the pulmonary veins, it returns to the heart and enters the left ventricle.
Blood returning from systemic circulation enters the heart at the right atrium. Blood from the pulmonary circulation enters the left atrium.
Blood that comes in to the right atrium comes from the pulmonary vein.
the lungs