The Circulation : Part 1

Hygienic Physiology: with Special Reference to the Use of Alcoholic Drinks and Narcotics
by Joel Dorman Steele, Ph.D.

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"No rest this throbbing slave may ask, Forever quivering o'er his task, While far and wide a crimson jet Leaps forth to fill the woven net, Which in unnumbered crossing tides The flood of burning life divides, Then, kindling each decaying part, Creeps back to find the throbbing heart."

Analysis of the Circulation

The Organs of the Circulation are the heart, the arteries, the veins, and the capillaries.

The Blood is the liquid by means of which the circulation is effected. It permeates every part of the body, except the cuticle, nails, hair, etc. The average quantity in each person is about eighteen pounds. It is composed of a thin, colorless liquid, the plasma, filled with red disks or cells, so small that about three thousand five hundred placed side by side would measure only an inch, and it would take sixteen thousand laid flat wise upon one another to make a column of that height. Under the microscope, they are found to be rounded at the edge and concave on both sides. They have a tendency to collect in piles like rolls of coin. The size and shape vary in the blood of different animals. Disks are continually forming in the blood, and are constantly dying - twenty million at every breath. - Draper.

The plasma also contains fibrin, albumin - which is found nearly pure in the white of an egg - and various mineral substances, as iron, lime, magnesia, phosphorus, potash, etc.

Uses of the Blood. - The blood has been called "liquid flesh"; but it is more than that, since it contains the materials for making every organ. The plasma is rich in mineral matter for the bones, and in albumen for the muscles. The red disks are the air cells of the blood. They contain the oxygen so essential to every operation of life. Wherever there is work to be done or repairs to be made, there the oxygen is needed. It stimulates to action, and tears down all that is worn out. In this process, it combines with and actually burns out parts of the muscles and other tissues, as wood is burned in the stove. The blood, now foul with the burned matter, the refuse of this fire, is caught up by the circulation, and whirled back to the lungs, where it is purified, and again sent bounding on its way.

There are then two different kinds of the blood in the body: the red or arterial, and the dark or venous.

Transfusion. - As the blood is really the "vital fluid" it would seem that feeble persons might be restored to vigor by infusing healthy blood into their veins. This hypothesis, so valuable in its possible results in prolonging human life, has been carefully tested. Animals which have ceased to breathe have therefore had their vitality recalled. In the seventeenth century the theory became a subject of special investigation. A maniac was restored to reason by the blood of a calf, and the most extravagant hopes were entertained. But many fatal accidents occurring, experiments upon human beings were forbidden by law, and transfusion soon fell into disuse. It has, however, been successfully practiced in several cases within the last few years, and is a method still in repute for saving lives.

Coagulation. - When blood is exposed to the air, it coagulates. This is caused by the solidifying of the fibrin, which entangling the disks, forms the "clot." The remaining clear, yellow liquid is the serum. The value of this peculiar property of the blood can hardly be overestimated. The coagulation soon checks all ordinary cases of bleeding.

The Heart is the engine which propels the blood. It is a hollow, pear- shaped muscle, about the size of the fist. It hangs, point downward, just to the left of the center of the chest. It is enclosed in a loose sac of serous membrane, called the pericardium. This secretes a lubricating fluid, and is smooth as satin.

The Movements of the Heart consist of an alternate contraction and expansion. The former is called the sys'-to-le, and the latter the di-as'-to-le. During the diastole, the blood flows into the heart, to be expelled by the systole. The alternation of these movements constitutes the beating of the heart which we hear so distinctly between the fifth and sixth ribs.

The Auricles And Ventricles - The heart is divided into four chambers. In an adult, each holds about a wineglassful. The upper ones, from appendages on the outside resembling the ears of a dog, are called auricles. are termed ventricles. The auricle and ventricle on each side communicate with each other, but the right and left halves of the heart are entirely distinct, and perform different offices. The left side propels the red blood; and the right, the dark. The auricles are merely reservoirs to receive the blood (the left auricle, as it filters in bright and pure from the lungs; the right, as it returns dark and foul from the tour of the body), and to furnish it to the ventricles as they need. Their work being so light, their walls are comparatively thin and weak. On the other hand, the ventricles force the blood (the left, to all parts of the body; the right, to the lungs), and are, therefore, made very strong. As the left ventricle drives the blood so much farther than the right, it is correspondingly thicker and stronger.

Need of Valves In The Heart. - As the auricles do not need to contract with much force simply to empty their contents into the ventricles below them, there is no demand for any special contrivance to prevent the blood from setting back the wrong way. Indeed, it would naturally run down into the ventricle, which is at that moment open to receive it. But, when the strong ventricles contract, especially the left one, which must drive the blood to the extremities, some arrangement is necessary to prevent it from returning into the auricle. Besides, when they expand, the "suction power" would tend to draw back again from the arteries all the blood just forced out. This difficulty is obviated by means of little doors, or valves, which will not let it go the wrong way.

The Tricuspid And Bicuspid Valves. - At the opening into the right ventricle, is a valve consisting of three folds or flaps of membrane, whence it is called the tricuspid valve and in the left ventricle, one containing two flaps, and named the bicuspid valve. These hang so loosely as to oppose no resistance to the passage of the blood into the ventricles; but, if any attempts to go the other way, it gets between the flaps and the walls of the heart, and, driving them outward, closes the orifice.