[continued from the Last Post.]The icon of romance, the object of Cupid’s arrow, the substance of Valentine’s cards. The ancient Egyptians measured truth by weighing the hearts of the dead. The Greeks believed the heart to be a forge, a furnace within which the impurities in blood were burnt. The reality is rather different.
The heart is actually a fist-sized mass of muscle, valves, and tubing, in fact, a pump that forces blood around your body.
The facts:
From about the fourth week of conception, until a couple of minutes prior to death, the heart thumps away. Usually one beat per second, sometimes more.
William Harvey, an English physician, discovered that the heart is a pump in a circulatory system that is predominantly a closed circuit. The main omission in Harvey’s knowledge was that he was unable to explain how blood got from arteries to veins. This was because the microscope had not yet been invented.
The speed at which the heart develops after conception highlights its vital role in survival. In order to live on, every cell in the body needs a continual supply of oxygen and nutrients. These are transported by blood, a physical fluid conveyor belt driven around the body by heart power.
Thus, in terms of embryological development, the heart and its major blood vessels are formed and activated well before any other organ.
By the time a foetus is eight weeks old, it possesses a tiny heart that is a miniature version of an adult’s. At this stage, the heart has four distinct chambers. These are linked two-by-two to form adjacent, self-contained, left and right pumps. A tough membrane, known as the septum, separates the two pumps.
An average person’s body contains eight to ten pints of blood. For the average adult, the heart is somewhat cone- or pear-shaped, and approximately the size of a man’s fist. The dimensions are nearly five inches long, about three inches across, and two and a half inches front to back.
The right pump drives blood to the lungs for oxygenation. Once “refreshed” this blood circulates back to the left pump, which in turn conveys it, with its cargo of oxygen, to the rest of the body.
The blood then returns to the right pump, completing the circuit.
[To be continued in the Next Post. Excerpted from the 'Lifescaping' seminar participant's manual. The 'Lifescaping' seminar is conducted by Dilip Mukerjea about four times a year under the auspices of the Singapore Insttitute of Management.]
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