PULMONARY CIRCULATION:
Deoxygenated blood is collected in the right atrium of the heart and is pumped into the right ventricle. Blood then moves to the pulmonary truck from the right ventricle into the pulmonary arteries to the lungs. Gas exchange occurs at the pulmonary capillaries and that is where the blood is oxygenated and CO2 is removed in the alveoli. Oxygenated blood returns back to the heart from the pulmonary vinens into the left atrium.
SYSTEMATIC CIRCULATION:
Oxygenated blood is collected in the left atrium which moves into the left ventricle and is pumped to the aorta. Arteries branch out of the aorta to the rest of the body where it goes into the capillaries where gas exchange occurs and becomes deoxygenated. the deoxygenated blood returns to the heart in two majour veins, the superior vena cava and the inferior vena cava, which both enter the right atrium.
