Blood vessel

“ But, when a portion only of the circumference is divided, the blood continues to flow through the aperture and onwards, as if into a smaller ramification of itself, no retraction or contraction of the vessel can occur, coagulation is slow, and the bleeding profuse. I have seen a wound of so small a vessel as the internal mammary prove almost instantaneously fatal. Wounds of the large internal vessels for the most part prove immediately fatal; as wounds of the heart, or the large vessels passing to and from its cavities, at the root of the lungs, or at the upper part of the liver. ”

“ The dilatation of arteries, more especially of the internal ones, is often very great; ultimately the internal coat gives way, and the external, with the surrounding tissues, yields in proportion as the blood diffuses itself. The internal tunic is occasionally burst in consequence of violent and sudden muscular exertion; and, even when the vessels are pretty limber and sound, effusion of lymph, and obliteration of the vessel ensue, or, more frequently, aneurism. ”

“ In arterial hæmorrhage the blood is bright red in colour, and escapes from the cardiac end of the divided vessel in pulsating jets synchronously with the systole of the heart. In vascular parts—for example the face—both ends of a divided artery bleed freely. The blood flowing from an artery may be dark in colour if the respiration is impeded. When the heart's action is weak and the blood tension low the flow may appear to be continuous and not in jets. The blood from a divided artery at the bottom of a deep wound, escapes on the surface in a steady flow. ”

“ There was one major difference between bleeding a man and bleeding a horse or cow, and that was the amount of strength required to open a vein. The considerable force needed to pierce the skin and the tunic of the blood vessel made the operation much more difficult to perform than human phlebotomy. ”

“ The rider assumes legs extending into the arterial branches beyond the place of obstruction, and a body which extends backward in the course of the circulation to the nearest branch. The result of the total obstruction of the vessel is to cut off the admission of arterial blood, producing a local anæmia. The contraction of the elastic tissues of the part propels toward the capillaries a certain quantity of the blood in the vessels beyond the point of obstruction, till this force becomes neutralized by the blood-pressure in the vessels surrounding the obstructed region. ”

“ When the blood is of a bright red colour, and comes out in jets, indicating that an artery is wounded, apply first a stream of cold water, iced if possible, from a large sponge, which will not only wash away all clots, dirt, &c., but promote contraction of the vessel, and perhaps arrest the bleeding at once. ”

“ Thrombosis—clotting in the vessel. Embolism, blocking of the vessel. Thrombus may form in any bloodvessel. Embolism occurs in arteries. Clot follows the blood current. Causes of clotting—fibrinogen, paraglobulin, fibrine ferment; foreign bodies; parasites; air; blood that has been exposed, transfusion; ærial germs; disease germs; chemical coagulants; high and low temperatures; breaches of endothelium; congestion or inflammation of the serosa; stasis of blood and extension of clot; ligature near a branch vessel: deoxidation and carbonization of blood, marasmus; neoplasms ”

“ Where bleeding is permissible, the blood should be drawn from the jugular in a full stream, from a large orifice, the finger being placed upon the pulse, and the flow arrested as soon as the blood is felt to pass along the vessel in a fuller, freer current, and the breathing is seen to be relieved. It can rarely be repeated with profit or safety, and in the vast majority of cases can be well dispensed with altogether. ”

“ That much more blood may be taken when the blood-vessels are in a state of morbid excitement and excitability, than at any other time. One of the uses of the blood is to stimulate the blood-vessels, and thereby to assist in originating and preserving animal life. In a healthy state of the vessels, the whole mass of the blood is necessary for this purpose; but in their state of morbid excitability, a much less quantity of blood than what is natural (perhaps in some cases four or five pounds) are sufficient to keep up an equal and vigorous circulation. ”

“ The severity of a hemorrhage depends upon the size of the vessel from which the blood escapes, though it may be stated that it is more serious when arteries are severed. If the wound in an artery is in the direction of its length, the blood escapes more freely than if the vessel is completely severed, because in the latter instance the severed ends retract, curl in, and may aid very much in arresting the flow. ”

“ There are two main blood vessels, an upper and a lower, which expand and contract alternately throughout their whole length, and thus maintain the circulation. The blood passes forward in the ventral vein, is pumped through the fine vessels of the gills, and collected into the upper artery. ”

“ Then the blood is carried to the lungs, where the fresh air you breathe in blows away the “smoke” and makes the blood red again.
The blood is pumped all over the body through tubes or pipes, called blood vessels. Those that carry the red blood out from the heart, we call arteries. They are deep down under the skin, and we cannot see them. The pipes that carry the purple blood from the muscles and other parts back to the heart again, we call veins; and some of these are so close to the surface that we can easily see them through the skin. ”

“ In consequence of this pumping power of the heart, the blood in the vessels is under considerable pressure, which is naturally increased if the blood-vessels are narrowed or contracted, and diminished if the blood-vessels are expanded or dilated. ”

“ The sudden congestion or filling and over-distention of the delicate blood-vessels of the organ operated upon, caused by placing it in a vacuum, is liable to rupture these minute vessels, causing the infiltration of blood into the tissues and giving rise to inflammation, and in some cases, to suppuration, mortification, sloughing and death. ”

“ As we all know, the large blood vessels are either arteries or veins, the arteries being blood vessels which are carrying blood away from the heart, and the veins vessels that are carrying blood toward the heart. If we start with an artery and trace it through the body, we find that it is continually giving off branches which in turn give off smaller branches, until finally the subdivisions are so small that we cannot trace them any further with the naked eye. In the days before the microscope was discovered, there was a great deal of question as to how these finest branches ended. ”

“ There is no proof of any structural defect in the blood vessels, and beyond the fact that there is a diminution in the number of blood-plates, it has not been demonstrated that there is any alteration in the composition of the blood. ”

“ But perhaps the most appropriate example is in the blood-vessels, whose inosculations are so numerous that even though large arteries and veins be tied, the blood will find its way through the smaller ones, which ultimately will so enlarge as to keep up the circulation nearly as well as before the injury. ”

“ And, to tell you the truth, while there is no learned man present to be angry with us, it is a very ill-chosen name, because it is venous blood which flows in this so-called artery. But the doctors have decided that all the vessels which run from the heart should be called arteries, and all those which go back to it veins, whatever may be the nature of the blood which they contain. We cannot help it, because they manage all these matters in their own way; but in that case it was scarcely worth their while to talk about arterial and venous blood. ”

“ The muscular coats of the arterial system are then brought into action by the stimulus of distention, and propel the blood to the mouths, or through the convolutions, which precede the secretory apertures of the various glands and capillaries.
In the vessels of the liver there is no intervention of the heart; but the vena portarum, which does the office of an artery, is distended by the blood poured into it from the mesenteric veins, and is by this distention stimulated to contract itself, and propel the blood to the mouths of the numerous glands, which compose that viscus. ”

“ And further, if the arteries take in and cast out air in the systole and diastole, like the lungs in the process of respiration, wherefore do they not do the same thing when a wound is made in one of them, as is done in the operation of arteriotomy? When the windpipe is divided, it is sufficiently obvious that the air enters and returns through the wound by two opposite movements; but when an artery is divided, it is equally manifest that blood escapes in one continuous stream, and that no air either enters or issues. ”

“ The examination of the blood, or of the vessels, in such cases, will by no means invariably indicate the presence of foreign matter after it has once become thoroughly mixed with the blood, nor will inflammation of the vein through which the fluid passes, be by any means invariably produced.
When a foreign substance is introduced into an artery, any immediate effects upon the blood may naturally be looked for in the system of capillaries which it supplies. If the blood then coagulates, local symptoms alone, will, in the first instance, be produced, and the constitution will remain unaffected. ”

“ Only the blood of man must be used. The direct giving of blood by connecting the radial artery of a relation to the median vein of a patient has been used as a means of effecting restoration. Blood may be withdrawn from the system slowly to the extent of 4 %, rapidly to the extent of 2 % of the body weight, without lowering the arterial pressure, owing to the compensatory contraction of the arterioles and the rapid absorption of fluid from the tissues into the blood. The withdrawal of the tissue-lymph excites extreme thirst and the great need for water which occurs after severe hemorrhage. ”

“ From these facts it is easy for any careful observer to learn that the blood enters an extremity by the arteries; for when they are effectively compressed nothing is DRAWN to the member; the hand preserves its color; nothing flows into it, neither is it distended; but when the pressure is diminished, as it is with the bleeding fillet, it is manifest that the blood is instantly thrown in with force, for then the hand begins to swell; which is as much as to say that when the arteries pulsate the blood is flowing through them, as it is when the moderately tight ligature is applied ”

“ Collections of matter formed on the membrane lining the heart and covering its valves, are liable to be detached and carried by the circulation to the brain, spleen, or liver, where they plug up some artery, and thus cause death of the parts which it supplies with blood. ”

“ A sufficiency of blood to distend it collects within the venous cistern. The arterial system, owin to its elasticity and contractility, empties. If the heart now begin to beat, blood is taken from the venous system and is driven into the arterial system., The arteries receive more blood than can escape through the capillary vessels, and the arterial side of the system becomes distended, until equilibrium is reached, and as much blood escapes into the venous side per unit of time as is delivered by the heart. ”

“ When the left auricle and ventricle together with the large divisions of the aorta, on opening the body, are found to contain blood, such blood is always black. The fact is familiar to those who are in the habit of dissecting. In exercising my pupils on the surgical operations, I have always observed that when the open arteries are not entirely empty, their contents are composed of venous blood. ”

“ You see, now, why it is so dangerous to wound a large artery: the blood spurts at every stroke of the heart, while in the veins there is no such pressure or direct connection; besides, as the veins are designed not to carry the blood from the heart, but to bring it back, they are also furnished with numerous valves that favor the flow of blood towards the heart, but not from it. ”

“ The unlimited use of stimulating animal food, on which they are from infancy fed, induces at an early age a highly plethoric state of the vascular system. The weaker over-distended vessels of the nose quickly yield to the increased impetus of the blood, and an active hemorrhage relieves the subject. ”

“ Hence the pulmonary arteries yawn nearest for the blood, and, being short, wide vessels, present the least resistance to the first rush of blood-- mainly venous blood for the right auricle. As they fill up, the back resistance in them becomes equal, and then greater, than the resistance at A, and the rush of blood, now of a mixed quality passes through that aperture. It selects the dorsal aorta, because the carotid arch, plugged by the carotid gland, offers the greater resistance. ”