A type of blood circulation system in which the blood flows through the heart twice. In this type of circulation, the pulmonary circulation is separate from the systemic circulation.
In this circulation, the heart consists of: the right side that pumps deoxygenated blood into the pulmonary section and the left side that pumps oxygenated blood into the systemic circulation. This is common among mammals and birds. This is in contrast to animals that have only one circulation system such as fish.
Compare: single cycle circulation
Mzunguko wa damu ni mfumo wa damu ambao damu hutiririka mara mbili kupitia moyo. Katika aina hii ya mzunguko wa damu, mzunguko wa damu wa mapafu ni tofauti na mzunguko wa damu wa mfumo. Katika mzunguko huu, moyo una sehemu ya kulia ambayo hupomba damu isiyo na oksijeni kwenye sehemu ya mapafu na upande wa kushoto ambayo hupomba damu yenye oksijeni kwenye mzunguko wa mfumo. Hilo ni jambo la kawaida miongoni mwa mamalia na ndege. Hii ni kinyume na wanyama ambao wana mfumo mmoja tu wa mzunguko wa damu kama vile samaki. Linganisha: mzunguko mmoja mzunguko