Pathway of blood flow through the heart
step 1
blood enters right atrium from superior and inferior venae cavae
step 9
blood flows through aortic valve into ascending aorta
step 4
blood flows through pulmonary valve into pulmonary trunk
step 10
blood in aorta is distributed to every organ in the body, where it unloads O2 and loads CO2
step 2
blood in right atrium flows through right AV valve into right ventricle
step 7
blood in the left atrium flows through left AV valve into left ventricle
step 5
blood is distributed by right and left pulmonary arteries to the lungs where it unloads CO2 and loads O2
step 6
blood returns from the lungs via pulmonary veins to left atrium
step 11
blood returns to right atrium via venae cavae
step 8
contraction of left ventricle (simultaneous with step 3) forces aortic valve open
step 3
contraction of right ventricle forces pulmonary valve open