Slide 1
The heart drives connected lung and body circuits
The heart sends blood through the lungs and through the rest of the body. Its right and left sides drive these connected circuits.
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The route is a loop: blood returning from the body reaches the right side before traveling to the lungs. Blood returning from the lungs enters the left side before leaving for the body.
Slide 2
Atria receive blood; ventricles pump it onward
Each side has an atrium that receives blood and a ventricle that pumps it onward. The chambers do different jobs.
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A wall called the septum separates the right and left sides. Keeping the flows separated lets the lung circuit and body circuit operate at different pressures.
Slide 3
Pressure changes open and close the valves
Heart valves open and close as pressure changes. Their leaflets help prevent blood from flowing backward between beats.
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The tricuspid and mitral valves sit between receiving and pumping chambers. The pulmonary and aortic valves guard the exits from the ventricles, so a valve problem affects a particular part of the route.
Slide 4
Electrical timing coordinates filling and pumping
An electrical signal coordinates the heartbeat. Filling and ejection depend on the chambers contracting in a useful sequence.
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The signal normally begins in the sinus node and travels through a conduction system. A pause before ventricular activation gives the atria time to contribute to ventricular filling.
Slide 5
Coronary arteries supply the heart muscle itself
The heart muscle also needs oxygenated blood. Coronary arteries deliver it to the tissue that keeps the circulation moving.
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Blood inside a chamber does not adequately nourish the entire thick muscle wall. Coronary vessels branch from the aorta, making the pump dependent on a circulation of its own.
Sources
- How Blood Flows through the Heart
NHLBI, NIH
- What the Heart Looks Like
NHLBI, NIH
- How the Heart Beats
NHLBI, NIH