The heart acts like a fountain, filling from above down its inner sides to its base, and emptying itself from below upward through its core by squirting up along both sides of its central septum.
The heart only holds what it contains for an instant, and then lets it go.
The atrial chambers of the upper heart are weaker suction pumps, drawing blood in from the tissues and lungs. The ventrical chambers of the lower heart are stronger pressure pumps, pushing blood out to the lungs and tissues. The heart alternates between upper and lower contraction.
Blood entering the heart is under much less pressure than blood leaving the heart. The valves that allow blood to enter the ventricles (tricuspid and bicuspid) are active rather than just passive valves, since muscles engage to open them from within. So opening the heart to receive is an action, like opening a door to receive a guest.
Blood is also calmed as it is received, since the tendinous chords that pull the valves open from inside the ventricles are themselves porous and so able to diffuse incoming turbulence.
Blood squeezed out of the heart all moves upward, but it does so in two separated streams that in the rest of the body do not flow in the same direction. One stream (from the right ventricle) flows laterally to bring carbon dioxide to the lungs, the other (from the left ventricle) flows more vertically to bring oxygen up or down to the tissues.
Freshly oxygenated blood flows to the heart before it flows to any other tissues. The heart feeds itself first with a ring of arteries around itself called a corona, or crown. They could also be imagined as a hug.
The right side of the heart pumps the whole body’s spent blood laterally toward the lungs to send waste carbon dioxide out to the air. During exhalation, the internal pressure of this spent blood chases the shrinking of the lungs.
The left side of the heart pumps fresh blood coming in from the lungs out to all of the body’s cells. This internal pumping of fresh blood is supported by the swelling of the lungs on inhalation, which squeeze the heart from the outside.
The heart rides on top of the moving diaphragm, lifting headward on every exhale or voiced expression, and sinking tailward on every inhale.
Heart muscle cells spontaneously coordinate their contractions and need external innervation only to set and maintain their pace. The heart is innervated from its surface inward, and is sensitive to what touches it.
When a person is in repose, their heart rests for the same amount of time as it works. When a person is active, the heart’s time for rest diminishes but its time for work remains the same. So accumulated stress on the heart is not from overwork but from under-rest.
The heart is surrounded by three bags of fascia that cushion, suspend and support it. The three bags are jointly called the pericardium. The inner two bags are separated by fluid that cushions the heart’s movement and forms a buffer between that movement and surrounding tissue, muffling the heart’s sound. The third and outer bag hangs the heart from the spine behind it.
Problems people have with their hearts seem to fall into several groups: 1. compressing and isolating the heart from what surrounds it 2. not letting the heart move, or rest 3. not letting the heart open, or close 4. forgetting what supports the heart. Maybe I am forgetting other groups, but this is a start.
It is the lowest freely moveable apex of the heart that sits left of center on the diaphragm. The top of the heart where it connects to its supplying and draining vessels is in midline.
Blood traveling from the heart to the lungs comes out the top back of the heart before forking toward the lungs to either side. It returns to the heart in roughly the same location, but lower down. Good heart function depends on keeping this central area above and behind the heart free of chronic compression. The heart must be free to lift. Emotionally this might mean allowing it to have joy.
Swallowed food and drink slide down through the esophagus behind the heart and land in the stomach beneath it. So the heart may carry some sense of being fed and protected from behind.
The heart arises from folded and subdivided tubing of the circulatory system. In the embryo it begins ahead of the mouth and is gradually folded into the chest as the mouth and brain curl over forward to follow it.
In utero, a baby always hears at least three rhythms: its own heartbeat, the heartbeat of its mother and its mother’s breathing. Hearing polyrhythms later in life may be a reminder of this time.
Before birth, a baby’s heart works mainly to circulate blood to and from the placenta. It does not need to get oxygen from its lungs or nutrition from its gut. The fetal heart pumps mainly from its inner or medial side, and orients the baby’s circulation medially through its navel to and from its mother.
With its first breath, a newborn dramatically changes heart. Blood pressure from the baby’s first lung expansion closes the oval window between its atria, making the heart’s medial side start to supply the lungs with spent blood. As work of the baby’s heart shifts more to its lateral side, the baby’s orientation toward vital sources of oxygen shifts from inward toward its mother to outward toward its lungs and through them toward the air. Many adults carrying birth trauma have not completed this transition, and lack awareness of the air around them.
© Erik Bendix, 2011