Igazi lithwalwa ngemibhobho ehamba igazi. Le mibhobho ke ngoonothumela noonobuyisa. Igazi eliya entliziyweni lihamba ngoonobuyisa. Igazi elishiya intliziyo lihamba ngoonobuyisa. Oyena nothumela mkhulu ophuma kwintliziyo nge-ventricle yangasekunene ngunothumela oyi-pulmonary. (I-Pulmonary ithetha ngokumalunga nemiphunga.) Oyena nothumela mkhulu ophuma nge-ventricle yangasekhohlo yi-aorta.