Circulatory and respiratory systems – heart rate during activity

Integrated ScienceLife ProcessesAges 13–14

The four-chambered heart contracts to pump blood through the pulmonary circuit (heart → lungs → heart) and the systemic circuit (heart → body → heart); the blood changes between bright red and dark red as gas exchange happens in the lungs and in body tissue. Choose an activity (sleep, rest, walk, run) to see heart rate, blood pressure, blood flow, breathing rate and tidal volume change, along with a real-time ECG trace and lungs inflating and deflating.