Refers to the blood flow to and from the lungs high blood pressure, elevated to over 140/90 (systole/diastole) the relaxed phase of the heartbeat; the lower number of blood pressure measurement blood that is oxygen-depleted; blood containing low levels of oxygen deoxygenated blood is returned from all over the body to the heart, it is then pumped on to the lungs via the pulmonary artery blood that is rich in oxygen; blood containing high levels of oxygen the protein in red blood cells used to carry oxygen in the blood the coronary arteries supply blood to the heart muscle 1. coronary circuit 2. deoxygenated blood 3. diastole 4. hemoglobin 5. hypertension 6. oxygenated blood 7. pulmonary artery 8. pulmonary circuit