Respiratory organ

“ The respiratory organs in mammals are the mouth, nose, larynx, trachea, bronchial tubes, and lung-tissue or air-cells proper. The windpipe is made up of cartilaginous rings completed by membrane, muscle, etc. (behind) . The bronchial tubes are the continuation of the windpipe, and branch tree-like until they become very fine. The air-cells are built round these latter. The lung-tissue is highly elastic. The lungs are made up of an elastic membrane, covered with flat cells, and very abundantly supplied with a mesh-work of the finest blood-vessels. ”

“ 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. ”

“ 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. ”

“ In the latter case, each little mass generally sets up in the surrounding tissue of the lungs, inflammation and suppuration, which, although only processes by which nature endeavours to expel the alien substance from the lung, may, by constant repetition, cause the destruction of the greater part of the respiratory organs. ”

“ 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 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. ”

“ Respiration occurs by means of the skin or of gills, or, in air-breathing forms, by 'trachea,' which are small branching tubes opening on the sides of the body. But in no case has the mouth or the digestive tract any connection with the respiratory system, a condition of affairs very different from that obtaining in the vertebrates. The nervous system consists of a brain, situated above the gullet, a nerve ring round the latter, and a double nerve cord running along the body, below the digestive canal. ”

“ 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. ”

“ 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 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. ”

“ The lungs spungy pneumatick and hydraulick organs, in themselves passive; but by the contraction of the diaphragm and intercostal muscles enlarging the capacity of the thorax, this ventilator is alternately distended with atmospheric air, and this sonorous fluid again quickly expelled, with either some noxious emanation from the body, or{173} decomposition of its own vital principle. Half the blood of the human body circulates thro’ this organ: its blood-vessels are numerous and large, and rise immediately from the heart ”

“ 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. ”

“ 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. ”

“ 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. ”

“ But however much the lungs vary in capacity, or the heart as to position in the respiratory motions, still the lungs are always closely applied to the thoracic walls. Between the pleura costalis and pulmonalis there occurs no interval in health. The thoracic parietes expand and contract to a certain degree; and to that same degree, and no further, do the lungs within the thorax expand and contract. By no effort of expiration can the animal expel all the air completely from its lungs, since by no effort of its own, can it contract thoracic space beyond the natural limit. ”

“ 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. ”

“ It is very probable that during life, the lungs are in very different degrees of congestion. We know that most chronic diseases of this organ occasion, when the patients take rather violent exercise, a sense of suffocation, oppression, &c. which appear to be owing only to the superabundance of blood, which, not being able to pass through this viscus as fast as it is sent there, is stopt, and checks the entrance and exit of the air. ”

“ 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. ”

“ 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. ”

“ 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 ”

“ Anyhow, the air gets to the lungs, otherwise we die; but the lungs, which are the largest single organ in the human body and in many ways the most adaptable, have this defect, and at the same time this enormous advantage in case of disease, that a very small part of them need be used in order to supply sufficient air to the stove of combustion. ”

“ 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. ”

“ By alternately increasing and diminishing [pg 100] the thoracic space, air is made to pass between the outside atmosphere and the interior of the lungs. Finding its way into the smallest divisions of the lungs, called the alveoli, the air comes very near a large surface of blood. By this means the carbon dioxide diffuses out of the blood, and the free oxygen enters. Through the combined action of the organs of respiration and the organs that move the blood and the lymph, the cells in all parts of the body are enabled to exchange certain gaseous materials with the outside atmosphere. ”

“ In the lungs, the air filling the air-cells would if left to itself soon lose all its oxygen and become loaded with carbonic acid; and the blood in the capillaries of the lungs would no longer be changed from venous to arterial, but would travel on to the pulmonary vein as dark and impure as in the pulmonary artery. Just as the blood in the muscle must be constantly renewed, so must the air in the lungs be continually changed. ”

“ 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. ”

“ 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. ”

“ Part 21 The explanation of the admission of air and respiration in those animals in which a lung is found, and especially in those in which it is full of blood, is to be found in the fact that it is of a spongy nature and full of tubes, and that it is the most fully charged with blood of all the visceral organs. All animals with a full-blooded lung require rapid refrigeration because there is little scope for deviation from the normal amount of their vital fire; the air also must penetrate all through it on account of the large quantity of blood and heat it contains. ”

“ A new element of many thousand pounds weight then presses upon the surface of its body. This atmospherick fluid, adulterated in cities with innumerable impurities and feculencies is drawn into its lungs: its diaphragm and muscles of respiration then begin to act, the lungs expand, and the respiration commences. The passage between the auricles of its heart and arterial duct are gradually closed up; the sphere of the circulation is extended; the whole current of blood in its frequent revolution hourly, passes through the lungs ”

“ And hence the absorbents of the lungs are less able to fulfil the whole of their duty. And part of the thin mucus, which is secreted into the air-cells, remains there unabsorbed, and occasions the difficult respiration, which awakes the patient. And the violent exertions of the muscles of respiration, which succeed, are excited by the pain of suffocation, for the purpose of pushing forwards the blood through the compressed capillaries, and to promote the absorption of the effused lymph. ”

“ It is in this way that the lungs are immediately connected with life, and hence the ancient physicians placed its functions among those which they called vital.
We understand also why pulmonary inflammations have so peculiar a character; why they are distinguished from others by many phenomena. No internal organ is more often inflamed than the lungs. ”

“ When the action of the lungs is seriously impeded, as in the case of lung diseases, the skin becomes colourless and waxy, and the vessels near the surface, especially those round the eyes, show a blue tinge, due to insufficient oxygenation of the blood. ”