Respiratory tract

“ All pulmonary lesions, from the least to the most localized, may be explained either by a subsidence of a less acute initial and diffuse involvement of the parenchyma, or by a less rapid and progressive spread of the necrotizing and inflammatory process from the upper respiratory tract through the bronchioles to the alveoli. ”

“ But just so soon as the general vitality is lowered, or there is an impairment of the normal condition of the epithelium lining the respiratory tract, a culture-medium is provided in which these germs flourish and grow. Anything which will cause an irritation or congestion of the mucous membrane of the throat and bronchial tubes furnishes the necessary conditions for the infection to take place. The germs themselves excite an acute inflammation, and the inflammation extends from the head or throat to the bronchial tubes, through the spread of the infective agent along the respiratory tract. ”

“ The trachea and bronchi of the infant are comparatively larger than in the adult, the air cells are much smaller, and for this reason a slight acute congestion will interfere almost as much with their function as will hepatization. This necessitates immediate action in all conditions which involve the respiratory tract, and especially those which affect the lungs or bronchi. In all such cases results are obtained very quickly under adjustments. In the child there is a greater tendency for the inflammation to spread in the lung tissue than in an adult. ”

“ Specificity requires that an exposure be associated with a single specific effect. Furthermore, if a disease has no other major risk factors (e.g., asbestos and mesothelioma) , the association is often very credible and the studies are the least susceptible to recall bias. The irritative symptoms of the eyes, skin, and upper respiratory tract reported in CCP studies are common effects with many risk factors. ”

“ Besides the heart and the great vessels the chest contains the lungs, the chief organ of respiration, which, with the rest of the respiratory system, will now be treated. The nose and mouth, through which the air first enters the body, have already been spoken of. From them the air passes through the larynx to the trachea, thence to the bronchi, and so to the lungs, where the supply of oxygen for the tissues is taken from the air by the hemoglobin of the blood. ”

“ The purity of the blood is influenced by the condition of the lungs. When the bronchial tubes and air-cells have become partially impervious to air, from pressure upon the lungs, from fluids in the chest, from tumors, or from the consolidation of the cells and tubes from disease,—as inflammation, or the deposition of yellow, cheesy matter, called tubercles,—the blood will not be purified, even if the air is pure, the lungs voluminous, and the respiratory movements unrestricted, as the air cannot permeate the air-cells. ”

“ Though the emphysematous lung is distended to a size equal to the healthy lung in deep inspiration, yet we know that emphysematous distention, being produced by extrabronchial air accumulation, is, in fact, obstructive to the respiratory act. ”

“ We can also now understand why, when the vessels of the lungs become congested and oppressed, and in those who are affected with serious diseases, it should be so dangerous and fatal a symptom when the respiratory organs become implicated. ”

“ A definite increase in the volume of the lungs is the consequence of frequent repetition of this supplemental respiration. The air-cells which are as a rule inactive, and which are reserved for cases of excessive respiratory strain, arise from their inaction; their walls, which are usually collapsed, and even stuck together, separate and give entrance to the air which can not find room in the confined space sufficient for ordinary breathing. ”

“ The impulse which comes from within, from the so-called respiratory centers, so excites the respiratory muscles that they cause the chest to execute the strongest breathing movements with the greatest ease, ventilating every portion of the lungs, filling every air-cell to its utmost capacity. ”

“ But more wonderful yet is its effect on the disorders of the respiratory organs. Under anything like favorable circumstances the lungs are, indeed, the most curable part of the human body. With every inspiration the balm of pure air can be brought into contact with the thousand times thousand air-cells of the respiratory apparatus, [2] and, as we breathe about twenty times per minute, the panacea can be applied twenty-seven thousand times in twenty-four hours. ”

“ Special breathing exercises, as well as those active muscular movements which induce a thirst for air, are beneficial to the lungs by maintaining the flexibility of the chest, strengthening the respiratory muscles, and ventilating the lungs. These movements also exercise a most extraordinary beneficial effect upon the stomach, liver, and other organs which lie below the diaphragm. Each time the diaphragm contracts, it gives the liver, stomach, and adjacent organs a hearty squeeze, so to speak, emptying out the blood contained in these parts as one may by compression empty a moist sponge. ”

“ In addition to the effect on the circulation, the respiratory movements keep up the nutrition and efficiency of the lungs, which in old age undergo a kind of atrophy, and also maintain the elasticity of the chest-walls, which are apt to become stiff through disuse, and so interfere with the movements of the lungs and pleura. ”

“ The coarser substance of the food is thrown out from the gastro-intestinal tract, the finer through the kidneys, others through the perspiratory tract, and the still finer particles through the breath in respiration. ”

“ We know that the respiratory system is constructed for the circulating: that the form, the extent, the complication of the respiratory apparatus depend entirely upon the quantity of blood that is to be regenerated, and the degree of perfection with which that regeneration is to be accomplished. ”

“ It here receives the oxygen from the atmosphere, and the chyle, or white blood, from the digested food, and becomes, in an instant, arterial blood, a vital principle, from which every solid and fluid of the body is constructed. Besides the lungs, Nature has provided another respiratory organ, a sort of supplemental lung, that, as well as being a covering to the body, _in_spires air and _ex_pires moisture;—this is the cuticle, or skin ”

“ The lungs have attained a high degree of efficiency. Each lung is an oval sac, and is transformed into a complicated system of tubes, at the end of which are the countless honeycomb-like respiratory cells, the whole lung being spongy. The main bronchus is continued straight down to the posterior end of the lung, and sends off during its course regular secondary bronchi, and these send off tertiary bronchi. The whole arrangement is very regular, the tubes coming off like rows of organ-pipes. Each lung hangs freely in the thoracic cavity. ”

“ In ordinary breathing the emission of air immediately follows the intake; expiration begins the moment inspiration ceases, and the respiration is completed. The elasticity of the lungs causes the diaphragm to rise and the walls of the chest to return to their natural position. ”

“ SPECIAL ORGANS OF THE FOOD-TRACT.—Another class of respiratory organs may now be distinguished, namely, those developed directly from the alimentary canal. Here belong the more highly specialized organs of the vertebrates. ”

“ If hepatisation exists in the anterior part of the lung the thick fleshy shoulder will forbid any satisfactory examination, but if in the middle portion only, while the respiratory murmur is lost it will be replaced by a strong blowing sound (bronchial respiration) because the noise of the air rushing through the larger bronchial tubes to the posterior healthy part of the lung is conveyed with greater force to the ear through the consolidated lung tissue. ”

“ Breathing by the lungs is simply the means by which the taking up of oxygen and the giving off of carbon dioxide by the cells is made possible.
HYGIENE OF RESPIRATORY ORGANS The liability of the lungs to attacks from such dread diseases as consumption and pneumonia makes questions touching their hygiene of first importance. Consumption does not as a rule attack sound lung tissue, but usually has its beginning in some weak or enfeebled spot in the lungs which has lost its "power of resistance." ”

“ The free and equable expansion of the lungs by full inspiration, necessarily takes place; this maintains their healthy structure, by keeping all the air-passages open and pervious; it prevents congestion in the pulmonary circulation, and at the same time provides more completely for the necessary chemical action on the blood, by changing, at each act of respiration, a sufficient proportion of the whole air contained in the lungs,—all objects of great importance, and all capable of being promoted, more or less, by the means in question. ”

“ The respiratory movements of the chest are sometimes very difficult to observe. They can always be better appreciated if the abdomen and chest are observed together. There are two methods to determine whether respiration is absolutely suspended or not. ”

“ The average person uses only about one seventh of his lung capacity in ordinary breathing, the rest of the air remaining at the bottom of the lung, being termed 'residual.' As this is vitiated by its stay in the lung, it does harm rather than good by its presence.... ”

“ In this case after a time the pulmonary capillaries, like the cutaneous ones, act with increased energy; the breathing, which was before quick, and the air thrown out at each respiration in less quantity, and cool to the back of the hand opposed to it, now becomes larger in quantity, and warmer than natural; which however is not accompanied with the sensation of heat in the membrane, which lines the air-vessels of the lungs, as in the skin. ”

“ Furthermore, the air expired from the infected lung is sensibly hot, especially if the inflammation is of the erysipelatous variety, and, as a consequence, the patient shows a disposition to draw long breaths, knowing that the cold air which he thus draws into his lungs will afford him some measure of relief. ”

“ Lungs' Respiration.—'The number of respirations is increased at the beginning of the stay, but returns to the normal number after a longer time, and probably the depth of the inspiration is also increased.' This is in accordance with our observations. The greater expansion of the chest, and the frequency with which patients and others volunteer the statement that they can breathe deeper, confirms the opinion that the depth of respiration is increased; more bulk of air being taken in to give to the lungs an equivalent amount of oxygen, greater depth of breathing must needs follow. ”

“ No organ is of greater importance to life than the lungs; and hence it is necessary not only to breathe a pure atmosphere, but also that we take in enough of it at every respiration to inflate the whole chest. The lungs may be said to commence with the soft lining of the trachea, and to extend in two huge lobes down into the chest ”

“ The lungs are the essential organs of respiration or ventilators of the body. They are two in number, separated from each other by the heart, are placed in a semi-distended state in the air-tight thorax, which we have seen they, together with the heart and great blood-vessels, completely fill. The lungs ultimately consist of air-cells, surrounded by dense plexuses of capillaries and nerves. The air-cells communicate with the exterior through the bronchial tubes, trachea, larynx, throat, and nose. ”

“ Capacity of the Lungs.—The lungs are not filled and emptied by each respiration. For while their full capacity, in the adult, is three hundred and twenty cubic inches, or more than a gallon, the ordinary breathing air is only one-sixteenth part of that volume, or twenty cubic inches, being two-thirds of a pint. Accordingly, a complete renovation, or rotation, of the air of the lungs does not take place more frequently than about once in a minute; and by the gradual introduction of the external air, its temperature is considerably elevated before it reaches the delicate pulmonary capillaries. ”

“ Simple diffusion through the narrow bronchial tubes could not possibly bring oxygen into the lung sacs fast enough to supply the requirements of the blood flowing through their walls. The situation is met by active lung ventilation; that is, by forcibly changing the air in the lungs at frequent intervals. The way in which this is done is, as we all know, by breathing. Breathing is nothing but a bellows movement of the chest by which air is alternately expelled and allowed to enter. ”

“ Man breathes by means of lungs; but who can understand their wonderful mechanism, so perfect in all its parts? Though every organ is subservient to another, yet each has its own office to perform. The minute air-cells are for the aeration of the blood; the larger bronchial tubes ramify the lungs, and suffuse them with air; the trachea serves as a passage for the air to and from the lungs, while at its upper extremity is the larynx, which has been fitly called the organ of the human voice. ”

“ A constant stream of water passes through the mouth into this common or respiratory sac, where, after having served its purpose of supplying oxygen to the system, a part is ejected directly through the vent, and the remainder, together with the nutrient particles, passes into the digestive tube, and thus finds its exit. ”

“ Consequently, any one who draws into his lungs this breath or conglomerated vapour, must necessarily absorb into his system the properties of that body from which it emanated, and from which it derived its being. For we know by experience that the air which enters the lungs dry, goes forth carrying with it moisture, [Pg 142] as may be seen by breathing on a glass, or in cold weather. Also, when we inhale the breath of any one who is ill, we are conscious of receiving infection. ”