What a wonderful organ is the heart! It starts to pulsate months before the child is born and continues throughout the life of the individual pausing to rest only between beats. In many individuals the heart never falters or scarcely misses a beat in the whole life span. Indeed a few persons live out their lives hardly knowing they have a heart, so well regulated are its functions.
The heart is wholly a muscular organ measuring 5 1/2 inches from base to apex, 3 1/2 inches across its broad surface, and 2 1/2 inches in thickness. In adult man it weighs about 11 ounces. It lies in the chest between the lungs and reaches up to the second rib. The upper part points upward and backward to the right; the lower part (apex) points downwards and outward to the left. About two thirds of its mass lies to the left of the median line.
The heart is enclosed in a serous sac, the pericardium. It has four chambers, viz., a right and left ventricle and a right and left auricle. A partition of fibrous tissue, the septum, separates the right and left chambers. So well regulated is the heart that each chamber functions independently to a certain extent. Between the auricles and ventricles are valves or doors composed of strong membrane, the left side having two doors while the right has three.
Openings into the arteries are also protected from return flow by half moon valves, called semilunar valves.
The heart is wholly concerned in the circulation of the blood throughout the body. Through its efforts the blood makes a circuit of the body every 23 seconds and all of the blood passes through the heart every 37 1/2 seconds. The blood leaves he left ventricle and enters the aorta by the contraction of the ventricle. It passes to all parts of the body, except the lungs, through the aortic branches. Capillaries pass the blood to return conduits, the veins, leading back to the heart. The right auricle receives the return flow. This auricle empties the blood into the right ventricle, which in turn pumps the blood to the lungs.
After the blood has exchanged its CO2 for oxygen it returns to the left auricle and thence to the left ventricle where it started from originally. The blood going through the stomach and intestines passes through the portal veins and capillaries to the hepatic veins. These veins in turn empty into the inferior vena cava, which returns the portal blood to the right auricle. Thus we have a general picture of the heart and its duties, also the many pipes it must force the blood through every second from birth to death. Some job! Is it not ridiculous to ascribe a defect in the stomach, in the liver, or even in the skin to a defect of the heart in failing to do its duty? The heart is ready and willing to furnish power but there is a break somewhere in the circuit of the systemic line, the pulmonary line, or the hepatic branches.
Right here I wish to make an observation, which I will enlarge upon later. There are chemical changes taking place at every relay station and some of them may be the cause. We have all seen cases of irregular heart following sunstroke or just from measles; not a defect of the heart at all. While in the army I once saw six hundred cases called disordered action of the heart, nearly all having very high blood pressure.
All had rapid heart action and some effort syndrome. None responded to cardiac therapy and not one was able to return to duty. My contention is that many of our heart cases where function is involved, may be due to incomplete chemical changes of the food and amino acids are absorbed before the complete split is accomplished. Also certain harmful acids are formed in the stomach or intestines producing gas and faulty heart action. To try to correct the heart in such conditions, except for emergency relief, would be bad practice.